git-for-each-ref doesn't return "the bit after $GIT_DIR/refs"

The documentation for git-for-each-ref said that the refname variable
would return "the part after $GIT_DIR/refs/", which isn't true.

Signed-off-by: Andy Parkins <andyparkins@gmail.com>
Signed-off-by: Junio C Hamano <junkio@cox.net>

Documentation/git-for-each-ref.txt

@@ -66,7 +66,7 @@ keys.
 For all objects, the following names can be used:
 
 refname::
-	The name of the ref (the part after $GIT_DIR/refs/).
+	The name of the ref (the part after $GIT_DIR/).
 
 objecttype::
 	The type of the object (`blob`, `tree`, `commit`, `tag`).