Ruby: Add support for =begin =end comments. Manual merge of #1121.

components/prism-ruby.js

@@ -6,7 +6,10 @@
  */
 (function(Prism) {
 	Prism.languages.ruby = Prism.languages.extend('clike', {
-		'comment': /#(?!\{[^\r\n]*?\}).*/,
+		'comment': [
+			/#(?!\{[^\r\n]*?\}).*/,
+			/^=begin(?:\r?\n|\r)(?:.*(?:\r?\n|\r))*?=end/m
+		],
 		'keyword': /\b(alias|and|BEGIN|begin|break|case|class|def|define_method|defined|do|each|else|elsif|END|end|ensure|false|for|if|in|module|new|next|nil|not|or|raise|redo|require|rescue|retry|return|self|super|then|throw|true|undef|unless|until|when|while|yield)\b/
 	});
 

examples/prism-ruby.html

@@ -1,8 +1,12 @@
 <h1>Ruby</h1>
 <p>To use this language, use the class "language-ruby".</p>
 
-<h2>Single-line comments</h2>
-<pre><code># This is a comment</code></pre>
+<h2>Comments</h2>
+<pre><code># This is a comment
+=begin
+Multi-line
+comment
+=end</code></pre>
 
 <h2>Strings</h2>
 <pre><code>"foo \"bar\" baz"
@@ -35,7 +39,7 @@ <h2>Known failures</h2>
 	If a failure is listed here, it doesn’t mean it will never be fixed. This is more of a “known bugs” list, just with a certain type of bug.
 </p>
 
-<h3>Comments that look like interpolation shows as ruby code</h3>
+<h3>Comments that look like interpolation show as ruby code</h3>
 <pre><code>#{my_var}</code></pre>
 
 <h3>Multi-line comments are not supported</h3>

tests/languages/ruby/comment_feature.test

@@ -1,11 +1,18 @@
 #
 # foobar
+=begin
+foo bar baz
+=end
+=begin
+=end
 
 ----------------------------------------------------
 
 [
 	["comment", "#"],
-	["comment", "# foobar"]
+	["comment", "# foobar"],
+	["comment", "=begin\r\nfoo bar baz\r\n=end"],
+	["comment", "=begin\r\n=end"]
 ]
 
 ----------------------------------------------------