feat(TextChannel): RateLimitPerUser (#2811)

* feat: Add TextChannel#rateLimitPerUser
Rename parameter in TextChannel#setRateLimitPerUser
feat: Add `rateLimitPerUser` param to ChannelData
fix: eslint

* docs: Updated typings

* fix: Requested changes

* fix: rateLimitPerUser being undefined when 0

When `rate_limit_per_user` is 0, the gateway does not send it (but REST does). When this is set to a non-zero number, this property starts to exist. Otherwise this will be `0`. Adding `|| 0` should do the trick changing `undefined` to `0`.

* fix: eslint

src/structures/GuildChannel.js

@@ -286,6 +286,7 @@ class GuildChannel extends Channel {
    * Lock the permissions of the channel to what the parent's permissions are
    * @property {OverwriteResolvable[]|Collection<Snowflake, OverwriteResolvable>} [permissionOverwrites]
    * Permission overwrites for the channel
+   * @property {number} [rateLimitPerUser] The ratelimit per user for the channel
    */
 
   /**
@@ -323,6 +324,7 @@ class GuildChannel extends Channel {
         user_limit: typeof data.userLimit !== 'undefined' ? data.userLimit : this.userLimit,
         parent_id: data.parentID,
         lock_permissions: data.lockPermissions,
+        rate_limit_per_user: data.rateLimitPerUser,
         permission_overwrites,
       },
       reason,