docs: update getByText docs (testing-library#123)

Closes testing-library#122 

**What**:

`getByText` section in the readme.

**Why**:

The current example is not accurate.

**How**:

Since the `exact` option is true by default, I use a regular exception with ignore case to find the desired element by text.

**Checklist**:

- [X] Documentation
- [ ] Tests N/A
- [X] Ready to be merged
- [X] Added myself to contributors table

Author: ruffle1986

.all-contributorsrc

@@ -347,6 +347,15 @@
         "doc",
         "test"
       ]
+    },
+    {
+      "login": "ruffle1986",
+      "name": "Tamas Fodor",
+      "avatar_url": "https://avatars0.githubusercontent.com/u/2196208?v=4",
+      "profile": "https://github.com/ruffle1986",
+      "contributions": [
+        "doc"
+      ]
     }
   ]
 }

README.md

@@ -16,7 +16,7 @@
 [![downloads][downloads-badge]][npmtrends]
 [![MIT License][license-badge]][license]
 
-[![All Contributors](https://img.shields.io/badge/all_contributors-34-orange.svg?style=flat-square)](#contributors)
+[![All Contributors](https://img.shields.io/badge/all_contributors-35-orange.svg?style=flat-square)](#contributors)
 [![PRs Welcome][prs-badge]][prs]
 [![Code of Conduct][coc-badge]][coc]
 
@@ -314,7 +314,7 @@ matching the given [`TextMatch`](#textmatch).
 
 ```javascript
 // <a href="/about">About ℹ️</a>
-const aboutAnchorNode = getByText(container, 'about')
+const aboutAnchorNode = getByText(container, /about/i)
 ```
 
 > NOTE: see [`getByLabelText`](#getbylabeltext) for more details on how and when to use the `selector` option
@@ -1055,7 +1055,7 @@ Thanks goes to these people ([emoji key][emojis]):
 | [<img src="https://avatars1.githubusercontent.com/u/1241511?s=460&v=4" width="100px;"/><br /><sub><b>Anto Aravinth</b></sub>](https://github.com/antoaravinth)<br />[💻](https://github.com/kentcdodds/dom-testing-library/commits?author=antoaravinth "Code") [⚠️](https://github.com/kentcdodds/dom-testing-library/commits?author=antoaravinth "Tests") [📖](https://github.com/kentcdodds/dom-testing-library/commits?author=antoaravinth "Documentation") | [<img src="https://avatars2.githubusercontent.com/u/3462296?v=4" width="100px;"/><br /><sub><b>Jonah Moses</b></sub>](https://github.com/JonahMoses)<br />[📖](https://github.com/kentcdodds/dom-testing-library/commits?author=JonahMoses "Documentation") | [<img src="https://avatars1.githubusercontent.com/u/4002543?v=4" width="100px;"/><br /><sub><b>Łukasz Gandecki</b></sub>](http://team.thebrain.pro)<br />[💻](https://github.com/kentcdodds/dom-testing-library/commits?author=lgandecki "Code") [⚠️](https://github.com/kentcdodds/dom-testing-library/commits?author=lgandecki "Tests") [📖](https://github.com/kentcdodds/dom-testing-library/commits?author=lgandecki "Documentation") | [<img src="https://avatars2.githubusercontent.com/u/498274?v=4" width="100px;"/><br /><sub><b>Ivan Babak</b></sub>](https://sompylasar.github.io)<br />[🐛](https://github.com/kentcdodds/dom-testing-library/issues?q=author%3Asompylasar "Bug reports") [🤔](#ideas-sompylasar "Ideas, Planning, & Feedback") [💻](https://github.com/kentcdodds/dom-testing-library/commits?author=sompylasar "Code") [📖](https://github.com/kentcdodds/dom-testing-library/commits?author=sompylasar "Documentation") | [<img src="https://avatars3.githubusercontent.com/u/4439618?v=4" width="100px;"/><br /><sub><b>Jesse Day</b></sub>](https://github.com/jday3)<br />[💻](https://github.com/kentcdodds/dom-testing-library/commits?author=jday3 "Code") | [<img src="https://avatars0.githubusercontent.com/u/15199?v=4" width="100px;"/><br /><sub><b>Ernesto García</b></sub>](http://gnapse.github.io)<br />[💬](#question-gnapse "Answering Questions") [💻](https://github.com/kentcdodds/dom-testing-library/commits?author=gnapse "Code") [📖](https://github.com/kentcdodds/dom-testing-library/commits?author=gnapse "Documentation") | [<img src="https://avatars2.githubusercontent.com/u/2747424?v=4" width="100px;"/><br /><sub><b>Josef Maxx Blake</b></sub>](http://jomaxx.com)<br />[💻](https://github.com/kentcdodds/dom-testing-library/commits?author=jomaxx "Code") [📖](https://github.com/kentcdodds/dom-testing-library/commits?author=jomaxx "Documentation") [⚠️](https://github.com/kentcdodds/dom-testing-library/commits?author=jomaxx "Tests") |
 | [<img src="https://avatars3.githubusercontent.com/u/725236?v=4" width="100px;"/><br /><sub><b>Alex Cook</b></sub>](https://github.com/alecook)<br />[📖](https://github.com/kentcdodds/dom-testing-library/commits?author=alecook "Documentation") [💡](#example-alecook "Examples") | [<img src="https://avatars3.githubusercontent.com/u/10348212?v=4" width="100px;"/><br /><sub><b>Daniel Cook</b></sub>](https://github.com/dfcook)<br />[💻](https://github.com/kentcdodds/dom-testing-library/commits?author=dfcook "Code") [📖](https://github.com/kentcdodds/dom-testing-library/commits?author=dfcook "Documentation") [⚠️](https://github.com/kentcdodds/dom-testing-library/commits?author=dfcook "Tests") | [<img src="https://avatars2.githubusercontent.com/u/21194045?s=400&v=4" width="100px;"/><br /><sub><b>Thomas Chia</b></sub>](https://github.com/thchia)<br />[🐛](https://github.com/kentcdodds/dom-testing-library/issues?q=author%3Athchia "Bug reports") [💻](https://github.com/kentcdodds/dom-testing-library/commits?author=thchia "Code") | [<img src="https://avatars1.githubusercontent.com/u/28659384?v=4" width="100px;"/><br /><sub><b>Tim Deschryver</b></sub>](https://github.com/tdeschryver)<br />[💻](https://github.com/kentcdodds/dom-testing-library/commits?author=tdeschryver "Code") [⚠️](https://github.com/kentcdodds/dom-testing-library/commits?author=tdeschryver "Tests") | [<img src="https://avatars3.githubusercontent.com/u/1571667?v=4" width="100px;"/><br /><sub><b>Alex Krolick</b></sub>](https://alexkrolick.com)<br />[💻](https://github.com/kentcdodds/dom-testing-library/commits?author=alexkrolick "Code") | [<img src="https://avatars2.githubusercontent.com/u/2224291?v=4" width="100px;"/><br /><sub><b>Maddi Joyce</b></sub>](http://www.maddijoyce.com)<br />[💻](https://github.com/kentcdodds/dom-testing-library/commits?author=maddijoyce "Code") | [<img src="https://avatars1.githubusercontent.com/u/25429764?v=4" width="100px;"/><br /><sub><b>Peter Kamps</b></sub>](https://github.com/npeterkamps)<br />[🐛](https://github.com/kentcdodds/dom-testing-library/issues?q=author%3Anpeterkamps "Bug reports") [💻](https://github.com/kentcdodds/dom-testing-library/commits?author=npeterkamps "Code") [⚠️](https://github.com/kentcdodds/dom-testing-library/commits?author=npeterkamps "Tests") |
 | [<img src="https://avatars2.githubusercontent.com/u/21689428?v=4" width="100px;"/><br /><sub><b>Jonathan Stoye</b></sub>](http://jonathanstoye.de)<br />[📖](https://github.com/kentcdodds/dom-testing-library/commits?author=JonathanStoye "Documentation") | [<img src="https://avatars2.githubusercontent.com/u/4126644?v=4" width="100px;"/><br /><sub><b>Sanghyeon Lee</b></sub>](https://github.com/yongdamsh)<br />[💡](#example-yongdamsh "Examples") | [<img src="https://avatars3.githubusercontent.com/u/8015514?v=4" width="100px;"/><br /><sub><b>Justice Mba </b></sub>](https://github.com/Dajust)<br />[💻](https://github.com/kentcdodds/dom-testing-library/commits?author=Dajust "Code") [📖](https://github.com/kentcdodds/dom-testing-library/commits?author=Dajust "Documentation") [🤔](#ideas-Dajust "Ideas, Planning, & Feedback") | [<img src="https://avatars3.githubusercontent.com/u/340761?v=4" width="100px;"/><br /><sub><b>Wayne Crouch</b></sub>](https://github.com/wgcrouch)<br />[💻](https://github.com/kentcdodds/dom-testing-library/commits?author=wgcrouch "Code") | [<img src="https://avatars1.githubusercontent.com/u/4996462?v=4" width="100px;"/><br /><sub><b>Ben Elliott</b></sub>](http://benjaminelliott.co.uk)<br />[💻](https://github.com/kentcdodds/dom-testing-library/commits?author=benelliott "Code") | [<img src="https://avatars3.githubusercontent.com/u/577921?v=4" width="100px;"/><br /><sub><b>Ruben Costa</b></sub>](http://nuances.co)<br />[💻](https://github.com/kentcdodds/dom-testing-library/commits?author=rubencosta "Code") | [<img src="https://avatars2.githubusercontent.com/u/4982001?v=4" width="100px;"/><br /><sub><b>Robert Smith</b></sub>](http://rbrtsmith.com/)<br />[🐛](https://github.com/kentcdodds/dom-testing-library/issues?q=author%3Arbrtsmith "Bug reports") [🤔](#ideas-rbrtsmith "Ideas, Planning, & Feedback") [📖](https://github.com/kentcdodds/dom-testing-library/commits?author=rbrtsmith "Documentation") |
-| [<img src="https://avatars3.githubusercontent.com/u/881986?v=4" width="100px;"/><br /><sub><b>dadamssg</b></sub>](https://github.com/dadamssg)<br />[💻](https://github.com/kentcdodds/dom-testing-library/commits?author=dadamssg "Code") | [<img src="https://avatars1.githubusercontent.com/u/186971?v=4" width="100px;"/><br /><sub><b>Neil Kistner</b></sub>](https://neilkistner.com/)<br />[💻](https://github.com/kentcdodds/dom-testing-library/commits?author=wyze "Code") | [<img src="https://avatars3.githubusercontent.com/u/1448597?v=4" width="100px;"/><br /><sub><b>Ben Chauvette</b></sub>](http://bdchauvette.net/)<br />[💻](https://github.com/kentcdodds/dom-testing-library/commits?author=bdchauvette "Code") | [<img src="https://avatars2.githubusercontent.com/u/777527?v=4" width="100px;"/><br /><sub><b>Jeff Baumgardt</b></sub>](https://github.com/JeffBaumgardt)<br />[💻](https://github.com/kentcdodds/dom-testing-library/commits?author=JeffBaumgardt "Code") [📖](https://github.com/kentcdodds/dom-testing-library/commits?author=JeffBaumgardt "Documentation") | [<img src="https://avatars0.githubusercontent.com/u/4658208?v=4" width="100px;"/><br /><sub><b>Matan Kushner</b></sub>](http://matchai.me)<br />[💻](https://github.com/kentcdodds/dom-testing-library/commits?author=matchai "Code") [📖](https://github.com/kentcdodds/dom-testing-library/commits?author=matchai "Documentation") [🤔](#ideas-matchai "Ideas, Planning, & Feedback") [⚠️](https://github.com/kentcdodds/dom-testing-library/commits?author=matchai "Tests") | [<img src="https://avatars2.githubusercontent.com/u/5779538?v=4" width="100px;"/><br /><sub><b>Alex Wendte</b></sub>](http://www.wendtedesigns.com/)<br />[💻](https://github.com/kentcdodds/dom-testing-library/commits?author=themostcolm "Code") [📖](https://github.com/kentcdodds/dom-testing-library/commits?author=themostcolm "Documentation") [⚠️](https://github.com/kentcdodds/dom-testing-library/commits?author=themostcolm "Tests") |
+| [<img src="https://avatars3.githubusercontent.com/u/881986?v=4" width="100px;"/><br /><sub><b>dadamssg</b></sub>](https://github.com/dadamssg)<br />[💻](https://github.com/kentcdodds/dom-testing-library/commits?author=dadamssg "Code") | [<img src="https://avatars1.githubusercontent.com/u/186971?v=4" width="100px;"/><br /><sub><b>Neil Kistner</b></sub>](https://neilkistner.com/)<br />[💻](https://github.com/kentcdodds/dom-testing-library/commits?author=wyze "Code") | [<img src="https://avatars3.githubusercontent.com/u/1448597?v=4" width="100px;"/><br /><sub><b>Ben Chauvette</b></sub>](http://bdchauvette.net/)<br />[💻](https://github.com/kentcdodds/dom-testing-library/commits?author=bdchauvette "Code") | [<img src="https://avatars2.githubusercontent.com/u/777527?v=4" width="100px;"/><br /><sub><b>Jeff Baumgardt</b></sub>](https://github.com/JeffBaumgardt)<br />[💻](https://github.com/kentcdodds/dom-testing-library/commits?author=JeffBaumgardt "Code") [📖](https://github.com/kentcdodds/dom-testing-library/commits?author=JeffBaumgardt "Documentation") | [<img src="https://avatars0.githubusercontent.com/u/4658208?v=4" width="100px;"/><br /><sub><b>Matan Kushner</b></sub>](http://matchai.me)<br />[💻](https://github.com/kentcdodds/dom-testing-library/commits?author=matchai "Code") [📖](https://github.com/kentcdodds/dom-testing-library/commits?author=matchai "Documentation") [🤔](#ideas-matchai "Ideas, Planning, & Feedback") [⚠️](https://github.com/kentcdodds/dom-testing-library/commits?author=matchai "Tests") | [<img src="https://avatars2.githubusercontent.com/u/5779538?v=4" width="100px;"/><br /><sub><b>Alex Wendte</b></sub>](http://www.wendtedesigns.com/)<br />[💻](https://github.com/kentcdodds/dom-testing-library/commits?author=themostcolm "Code") [📖](https://github.com/kentcdodds/dom-testing-library/commits?author=themostcolm "Documentation") [⚠️](https://github.com/kentcdodds/dom-testing-library/commits?author=themostcolm "Tests") | [<img src="https://avatars0.githubusercontent.com/u/2196208?v=4" width="100px;"/><br /><sub><b>Tamas Fodor</b></sub>](https://github.com/ruffle1986)<br />[📖](https://github.com/kentcdodds/dom-testing-library/commits?author=ruffle1986 "Documentation") |
 
 <!-- ALL-CONTRIBUTORS-LIST:END -->