Added and fixed a bunch of docs stuff (#1767)

- Fixed a common copy paste fail `the the <thing>` in various places
- Apparently I can't type Resolvable correctly,
Fixed that wherever applicable
- Documented GroupDMChannel#nicks so that it will be displayed on the docs
- GroupDMChannel#icon is nullable
- Removed empty InviteOptions typdef, as its properties are now documented in GuildChannel#createInvite
- MessageMentions#channels is no longer nullable
- RoleData#permissions takes a PermissionResolvable or an array of them
- Webhook#avatar is nullable
- Added HTTPOptions typedef and added it to ClientOptions typedef
- ClientUserChannelOverride#muted is for a channel and not a guild directly

src/structures/interfaces/Collector.js

@@ -186,7 +186,7 @@ class Collector extends EventEmitter {
   collect() {}
 
   /**
-   * Handles incoming events from the the `handleDispose`. Returns null if the event should not
+   * Handles incoming events from the `handleDispose`. Returns null if the event should not
    * be disposed, or returns the key that should be removed.
    * @see Collector#handleDispose
    * @param {...*} args Any args the event listener emits