Configuration translations cannot be shipped in modules/profiles

Don't love adding language-module specific code there, but a) didn't really feel worth factoring that out somehow at this point. We can always do that later b) language module is not really "just another module" and c) http://grep.xandeadx.ru/search?text=addCollections&filename= doesn't reveal any other usages of "addCollections" which is what is needed in order to support config installation of collections (regardless of Config Overlay). The only ones are Organic Groups Site Manager → and Variants → but neither of those have any releases at the time of writing.

Test-only job fails correctly, as the language override is not detected, and, thus, not removed on export: https://git.drupalcode.org/project/config_overlay/-/jobs/6008977

So looking closely

$targetStorage->read('core.extension')['language']

doesn't really make sense, it should be

$targetStorage->read('core.extension')['module']['language']

Found that out immediately when trying the new release. 🫤 Sorry about that!

I was so confident about this working because of the test coverage, so this exposes that the test coverage really is only testing the export code-path and not the import code-path - but for the "existing-config" tests (but I didn't add an existing-config test with language overrides here).

...so will add such a test now with the quick fix and then add a follow-up issue to improve the test coverage, to test both import and export in all cases.

Alrighty that was more "fun" that I had hoped for, but it's fixed now and I opened 📌 Improve test coverage to test the import code path Active as the follow-up. Marking fixed again and will create a release now with this.