All of the .po files can be excluded from the spelling checker, they're automatically updated from the source.

That's what I thought, but I had been told otherwise in #11735 (comment).

Any way, these updates are in a separate commit, they would be easy to discard.

If we change a localized string, I think what is autogenerated is an empty translation, hence we probably need to manually update translations in this case but I may be wrong.

co-ordinates is fine

Both co-ordinate and coordinate are fine, especially in British English according to dictionaries. However, the Google Ngram Viewer shows coordinate in wider use, including in the British English corpus strangely enough.

It's up to you, but what's wrong with following common use when targetting a large and international audience?

Even though co-ordinate is fine, I personally prefer one without "-". Also it removes one character from the code base so it's technically an optimization!

How about a compromise and use "coördinates" like the New Yorker! 🙃

https://www.newyorker.com/culture/culture-desk/the-curse-of-the-diaeresis