Text not found in multilingual content

Lets update for 2.0.x and add some test coverage

Adding a tag for test coverage per @smustgrave

flagbrad → changed the visibility of the branch 3266343-text-not-found to hidden.

me, https://www.drupal.org/u/javi-er → , https://www.drupal.org/u/rfay → helped mentor Brad. Thanks Brad! ping us later if we can help more!

Worked on this at DrupalCon Atlant 2025 as a first contribution. I had noted this issue 8 months ago and thought I'd try addressing it since my website has 27 languages and runs into this problem all the time.

Got the issue fork caught up (rebased, essentially) to the 2.0.x main branch. Still needs work because (a) logic is still incomplete, (b) probably way too few guards or null checks, and (c) needs test coverage. Thanks to mentors Randy Fay and Cathy T and Javier!