gui: Remove tooltip shown over whole modal

Changed the attribute 'title' (reserved) to 'heading' for the modal
template

GitHub-Pull-Request: https://github.com/syncthing/syncthing/pull/3281

gui/default/syncthing/core/restartingDialogView.html

@@ -1,3 +1,3 @@
-<modal id="restarting" status="info" icon="refresh" title="{{'Restarting' | translate}}">
+<modal id="restarting" status="info" icon="refresh" heading="{{'Restarting' | translate}}">
 	<p><span translate>Syncthing is restarting.</span> <span translate>Please wait</span>...</p>
 </modal>