Fix wrong occurence of variables

vim/neosnippets/go.snip

@@ -2,7 +2,7 @@ snippet     middleware
 options     head
     func ${1}(rw http.ResponseWriter, r *http.Request, next http.HandlerFunc) {
         ${2}
-        next(r, rw)
+        next(rw, r
     }
 
 snippet     handler