Fix GAC filter errors

Problem/Motivation

I didn't give much attention to that block. There are some custom things from legacy code in web/modules/contrib/google_analytics_counter/src/Plugin/Filter/GoogleAnalyticsCounterFilter.php:

      // Display the page views.
      // [gac] will detect the current node's count.
      //
      // [gac|all] displays the totalsForAllResults for the given time period,
      // assuming cron has been run. Otherwise will print N/A.
      //
      // [gac|1234] displays the page views for node/1234.
      // Currently not working.
      //
      // [gac|node/1234] displays the page views for node/1234.
      // Currently not working.
      //
      // [gac|path/to/page] displays the pages views for path/to/page.
      // Currently not working.

Try these out. And if it works, it needs to be included in the documentation at #3368166: Update module documentation about 4.0.0 usage and new features.

Steps to reproduce

Proposed resolution

Remaining tasks

User interface changes

API changes

Data model changes