update-po: Update/no changes report

[strarsis]

Feature Request

• Yes, I reviewed the contribution guidelines.

Describe your use case and the problem you are facing
(Side note: The new update-po subcommand is awesome!)

Currently it will report that the PO files were updated, even they hadn't changed (because the POT file hadn't changed).

Describe the solution you'd like
update-po should either report updated files or files that didn't need an update/changing.

Some examples:

Success: Updated 0 files. 1 file unchanged.

Success: Updated 1 file.

Success: Updated 4 files. 2 files unchanged.

This also helps spotting the need for adding/updating translations without using something like a diff tool or inspecting the last modified date of the POT file(s).

[swissspidy]

Thanks for sharing this suggestion 👍

Would need to check if it's easily possible to detect changes/modifications like that.