Print more user friendly error when --python version not found

[Gitznik]

• I have added an entry to docs/changelog.md

Summary of changes

Resolves #1089

Capture FileNotFound error during the install command and exit with a meaningful error message if it indicates that the provided python version was not found.

I think it would actually be nice to do the handling in venv.create_venv which is where the error surfaces. This would mean that the handling is uniform for all places that use this functionality (commands/run, commands/common, commands/install), bit it would also introduce a return value to this function.

def create_venv(...) -> None: -> def create_venv(...) -> EXIT_CODE_OK | EXIT_CODE_SPECIFIED_PYTHON_EXECUTABLE_NOT_FOUND:

If that's desired I'm happy to change the code accordingly.

Test plan

Tested by running nox -s tests-3.12

$ python3 src/pipx install --python python3.2 cowssay
> No executable for the provided Python version 'python3.2' found.
> Please make sure the executable name is on your PATH/the path to the executable is correct.

[gaborbernat]

CI failing.

[Gitznik]

CI failing.

Windows was not covered, should be fixed now.

[chrysle]

Please rebase.

[chrysle]

Indentation never works with those suggestions :-(

[Gitznik]

Indentation never works with those suggestions :-(

Yeah that would be too easy. Does the message look fine to you now? I got rid of the newline as it is stripped by pipx_wrap anyways.

Looks like this now:
No executable for the provided Python version 'python3.2' found. Please make sure the executable name is on your PATH / the path to the executable is correct., one line.

[chrysle]

Thanks! Unfortunately, one release chases the other these days...
I'm afraid you'll have to rebase once more.