Update article.md

Fix typo, minor grammar fix.

Author: deisner

Diff for: 4-binary/02-text-decoder/article.md

@@ -2,7 +2,7 @@
 
 What if the binary data is actually a string? For instance, we received a file with textual data.
 
-The build-in [TextDecoder](https://encoding.spec.whatwg.org/#interface-textdecoder) object allows to read the value into an actual JavaScript string, given the buffer and the encoding.
+The built-in [TextDecoder](https://encoding.spec.whatwg.org/#interface-textdecoder) object allows one to read the value into an actual JavaScript string, given the buffer and the encoding.
 
 We first need to create it:
 ```js