template modifications

Hello. Can you please tell me. Is it possible to configure the template modifier so that when you save it is not closed? Because when you change it, it constantly opens the general Template modifications page.

hi i'm writing add-on for sub forum icons how do I make the template change? this did not happen &.subNodeLink--forum:before, &.subNodeLink--category:before { .m-faContent( {{$xf.options.sF_SubForumManager_unreadSubforumIcon ? @fa-var-comments}} ); }