FR: Tool for reviewing translation PR to recognize a 'fuzzy' translation has been updated but not un-marked

[MichaelChirico]

E.g. in https://github.com/Rdatatable/data.table/pull/5875/files -- translator missed the detail that, when updating a translation marked fuzzy, we should also remove the , fuzzy notation and the #| comments with the guessed translation. It's also easy for a reviewer to miss this in a huge batch of translations.

This creates some toil when we need to (as developer) read through the old PR diff to see which translations were touched/not to tell whether they can safely have , fuzzy removed, or if they still need a review from translator eyes.

Not sure the right interface for this, but such tooling for developers to vet incoming translation PRs would be something to build on starting with this.