Ruby: Override 'class-name' definition (#2135)

Unlike other C-like languages, in Ruby objects don't get initialized by
using `new Object` but `Object.new`. So whatever comes after `new`
probably isn't a classname.

components/prism-ruby.js

@@ -13,6 +13,13 @@
 				greedy: true
 			}
 		],
+    'class-name': {
+      pattern: /(\b(?:class)\s+|\bcatch\s+\()[\w.\\]+/i,
+      lookbehind: true,
+      inside: {
+        'punctuation': /[.\\]/
+      }
+    },
 		'keyword': /\b(?:alias|and|BEGIN|begin|break|case|class|def|define_method|defined|do|each|else|elsif|END|end|ensure|extend|for|if|in|include|module|new|next|nil|not|or|prepend|protected|private|public|raise|redo|require|rescue|retry|return|self|super|then|throw|undef|unless|until|when|while|yield)\b/
 	});
 

tests/languages/ruby/method_definition_feature.test

@@ -32,7 +32,7 @@ end
   "diameter",
   ["punctuation", ")"],
   ["keyword", "new"],
-  ["class-name", ["diameter"]],
+  " diameter ",
   ["operator", "/"],
   ["number", "2"],
   ["keyword", "end"],