docs: Fixed some missing docstrings or incorrect return types (#2093)

* Fix some missing doc strings
Mainly just readonly tags

* Return an error when guild#allowDMs is ran from a bot account, and fix some return types

* WebhookClient implements Webhook, doesn't extend it

* Fix Client#rateLimit docs not showing what it returns

Cause I wanted to handle this event only to see no return props 🤔

* Actually make Client#rateLimit show the right info

Its an object with all the info

src/util/Constants.js

@@ -52,7 +52,7 @@ exports.DefaultOptions = {
    * WebSocket options (these are left as snake_case to match the API)
    * @typedef {Object} WebsocketOptions
    * @property {number} [large_threshold=250] Number of members in a guild to be considered large
-   * @property {boolean} [compress=true] Whether to compress data sent on the connection
+   * @property {boolean} [compress=false] Whether to compress data sent on the connection
    * (defaults to `false` for browsers)
    */
   ws: {