Fix bad reference-style link.

text/0000-document_all_features.md

@@ -66,7 +66,7 @@ The Ember core team agreed, and embraced the principle outlined in [this comment
 
 > No version shall be released until guides and versioned API documentation is ready. This will allow newcomers the ability to understand the latest release. ([@guarav0])
 
-[guarav0]: https://github.com/emberjs/rfcs/pull/56#issuecomment-114339423
+[@guarav0]: https://github.com/emberjs/rfcs/pull/56#issuecomment-114339423
 
 One of the main reasons not to adopt this approach, that it might block features from landing as soon as they otherwise might, was [addressed][@eccegordo] in that discussion as well: