updated the URL for emoji cheat sheet

Author: aollier

book/06-github/sections/2-contributing.asc

@@ -406,7 +406,7 @@ Not that this is incredibly useful, but it does add an element of fun and emotio
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 There are actually quite a number of web services that make use of emoji characters these days. A great cheat sheet to reference to find emoji that expresses what you want to say can be found at:
 
-http://www.emoji-cheat-sheet.com
+https://www.webfx.com/tools/emoji-cheat-sheet/
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 ===== Images