Add EXLskills Live Coding Interviews as real-world use case

Author: svarlamov

doc/realworld.html

@@ -76,6 +76,7 @@ <h2>CodeMirror real-world uses</h2>
       <li><a href="http://eloquentjavascript.net/chapter1.html">Eloquent JavaScript</a> (book)</li>
       <li><a href="http://emmet.io">Emmet</a> (fast XML editing)</li>
       <li><a href="https://github.com/espruino/EspruinoWebIDE">Espruino Web IDE</a> (Chrome App for writing code on Espruino devices)</li>
+      <li><a href="https://exlskills.com/learn-en/talent/interviews">EXLskills Live Interivews</a></li>
       <li><a href="http://www.fastfig.com/">Fastfig</a> (online computation/math tool)</li>
       <li><a href="https://metacpan.org/module/Farabi">Farabi</a> (modern Perl IDE)</li>
       <li><a href="http://blog.pamelafox.org/2012/02/interactive-html5-slides-with-fathomjs.html">FathomJS integration</a> (slides with editors, again)</li>