enabled thread title pings autocomplete

Author: Oaphi

app/assets/javascripts/comments.js

@@ -236,7 +236,7 @@ $(() => {
    * @type {Record<`${number}-${number}`, Record<string, number>>}
    */
   const pingable = {};
-  $(document).on('keyup', '.js-comment-field', pingable_popup);
+  $(document).on('keyup', '.js-comment-field, .js-thread-title', pingable_popup);
 
   /**
    * @type {QPixelPingablePopupCallback}

app/views/comments/_new_thread_modal.html.erb

@@ -39,7 +39,11 @@
         You can give your comment thread a title. If you leave this blank, the beginning of the initial comment will
         be shown.
       </span>
-      <%= text_field_tag :title, '', class: 'form-element', data: { character_count: ".js-character-count-thread-title" } %>
+      <%= text_field_tag :title, '',
+                         class: 'form-element js-thread-title',
+                         data: { post: post.id,
+                                 thread: '-1',
+                                 character_count: ".js-character-count-thread-title" } %>
       <%= render 'shared/char_count', type: 'thread-title' %>
 
       <%= submit_tag 'Create thread', class: 'button is-filled', id: "create_thread_button_#{post.id}", disabled: true %>