docs(ThreadMember): fix docblock async return type (#10058)

packages/discord.js/src/structures/ThreadMember.js

@@ -102,7 +102,7 @@ class ThreadMember extends Base {
   /**
    * Removes this member from the thread.
    * @param {string} [reason] Reason for removing the member
-   * @returns {ThreadMember}
+   * @returns {Promise<ThreadMember>}
    */
   async remove(reason) {
     await this.thread.members.remove(this.id, reason);