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.
if (mw.config.get('wgPageName') == "Special:Watchlist") {

   $('#mw-watchlist-resetbutton').remove();
   $('.mw-watched').contents().unwrap();

}

if (mw.config.get('wgAction') == "history") {

   $('.updatedmarker').remove();

}