Ignore checking formatting if no formatted files are staged

[legleux]

I'm constantly harassed to follow the rules when I'm not doing anything relevant.

This is an attempt to ameliorate that rather than --no-verify or just disabling hooks altogether. :mushroom: :cloud:

Somebody might want to confirm basename is included with macOS.

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 67.77%. Comparing base (c795cf3) to head (ef6ab00).

Additional details and impacted files

```diff @@ Coverage Diff @@ ## develop #1469 +/- ## ======================================== Coverage 67.77% 67.77% ======================================== Files 233 233 Lines 9419 9419 Branches 5254 5254 ======================================== Hits 6384 6384 Misses 1654 1654 Partials 1381 1381 ```

:umbrella: View full report in Codecov by Sentry.
:loudspeaker: Have feedback on the report? Share it here.