replaced string `discussion` wit `thread` in comment-button template

app/views/shared/notes/_comment_button.html.haml

@@ -18,11 +18,11 @@
 
       %li.divider.droplab-item-ignore
 
-      %li#discussion{ data: { value: 'DiscussionNote', 'submit-text' => _('Start discussion'), 'close-text' => _("Start discussion & close %{noteable_name}") % { noteable_name: noteable_name }, 'reopen-text' => _("Start discussion & reopen %{noteable_name}") % { noteable_name: noteable_name } } }
+      %li#discussion{ data: { value: 'DiscussionNote', 'submit-text' => _('Start thread'), 'close-text' => _("Start thread & close %{noteable_name}") % { noteable_name: noteable_name }, 'reopen-text' => _("Start thread & reopen %{noteable_name}") % { noteable_name: noteable_name } } }
         %button.btn.btn-transparent
           = icon('check', class: 'icon')
           .description
-            %strong= _("Start discussion")
+            %strong= _("Start thread")
             %p
               = succeed '.' do
                 - if @note.noteable.supports_resolvable_notes?