Some encouragement for visitors of PrismJS.com to request new languag…

…es (#1760)

This adds a direct link to our Github issue page, encouraging visitors to make a new issue to request a new language.

index.html

@@ -201,10 +201,12 @@ <h2>Usage with Node</h2>
 
 </section>
 
-<section id="languages-list" class="language-markup">
+<section class="language-markup">
 	<h1>Supported languages</h1>
 	<p>This is the list of all <span id="languages-list-count"></span> languages currently supported by Prism, with
 		their corresponding alias, to use in place of <code>xxxx</code> in the <code>language-xxxx</code> (or <code>lang-xxxx</code>) class:</p>
+	<div id="languages-list"></div>
+	<p>Couldn’t find the language you were looking for? <a href="https://github.com/PrismJS/prism/issues" target="_blank">Request it</a>!</p>
 </section>
 
 <section id="plugins">