* doc/syntax/refinements.rdoc : Fix a missing quote

Patch by Robin Dupret. [Fix GH-271]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@40586 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

doc/syntax/refinements.rdoc

@@ -18,7 +18,7 @@ Here is a basic refinement:
 
   class C
     def foo
-      puts "C#foo
+      puts "C#foo"
     end
   end