Note: After saving, you have to bypass your browser's cache to see the changes. Google Chrome, Firefox, Microsoft Edge and Safari: Hold down the ⇧ Shift key and click the Reload toolbar button. For details and instructions about other browsers, see Wikipedia:Bypass your cache.
jQuery(document).ready(function($) {
	if(mw.config.get('wgPageName') === 'Special:Watchlist') {
		mw.loader.using(['mediawiki.util']).done( function() {
			var portletlink = mw.util.addPortletLink('p-tb','#','Unwatch deleted','t-unwatch-deleted');
			$(portletlink).click(function(e) {
				e.preventDefault();
				unwatchDeleted();
			});
		});
	}
	
	function unwatchDeleted() {
		$('li.mw-changeslist-log-delete span.mw-changeslist-line-prefix a').each(function() {
			$(this).click();
		});
	}
});