Changing docs in CakeRequest:accepts() as they were misleading, you a…

…re required to pass a correct mimetype and not an alias

lib/Cake/Network/CakeRequest.php

@@ -656,7 +656,7 @@ public function subdomains($tldLength = 1) {
  *
  * #### Check for a single type:
  *
- * `$this->request->accepts('json');`
+ * `$this->request->accepts('application/json');`
  *
  * This method will order the returned content types by the preference values indicated
  * by the client.