fix groovy comments at eof

closes #279

lib/rouge/lexers/groovy.rb

@@ -50,7 +50,7 @@ module Rouge
         # whitespace
         rule /[^\S\n]+/, Text
-        rule %r(//.*?\n), Comment::Single
+        rule %r(//.*?$), Comment::Single
         rule %r(/[*].*?[*]/)m, Comment::Multiline
         rule /@\w[\w\d.]*/, Name::Decorator
         rule /(class|interface)\b/,  Keyword::Declaration, :class

spec/visual/samples/groovy

@@ -95,3 +95,5 @@ private class WorkflowParser {
         map
     }
 }
+
+// comment at "EOF"