fix typo

Dane Springmeyer · Dane Springmeyer · commit b9f2af6f8790 · 2012-03-05T15:48:04.000-08:00
diff --git a/docs/contributing.markdown b/docs/contributing.markdown
@@ -99,7 +99,7 @@ If you see bits of code around that do not follow these please don't hesitate to
 
     std::string const& variable_name // preferred, for consistency
 
-    std::string const& variable_name // no
+    const std::string & variable_name // no
 
 #### Pass built-in types by value, all others by const&
 
