[Bug other/122742] New: Update GCC Testing Efforts page

[sjames at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=122742

            Bug ID: 122742
           Summary: Update GCC Testing Efforts page
           Product: gcc
           Version: 16.0
            Status: UNCONFIRMED
          Keywords: documentation
          Severity: normal
          Priority: P3
         Component: other
          Assignee: unassigned at gcc dot gnu.org
          Reporter: sjames at gcc dot gnu.org
  Target Milestone: ---

https://gcc.gnu.org/testing/ is a bit dated and doesn't mention a lot of the
efforts we do these days (different CI systems, the distro work, ...).

I'll update it.