Add option to hide python version

[MaxSchambach]

This adds a simple option (via set -g theme_hide_python_version yes) to hide the Python version using virtualenv.

Personally, I believe most people only develop in Python 3 nowadays, so having the extra space just to show the version seems unnecessary.

PS: thanks for this awesome theme! 😀

[bobthecow]

This is a great point. I'm wondering if there's a way we can do it without config, so that by default it's the best experience for the most people? The general principle in bobthefish is only to show interesting information by default, which is why it suppresses things like "current {node,ruby,python,whatever} version" if you're not using some sort of version manager or local env managed version.

Possibly we could do one of the following:

• Only show the version glyph if the current version is different from the system Python version.
• Never show the version glyph for Python 3, only Python 2.
• Add a third value (verbose?) to the theme_display_virtualenv to opt into showing the version glyph.

I'm leaning toward a combination of the last two options. By default, only show Python 2 glyph (because that's interesting, in 2024!) but if theme_display_virtualenv is set to verbose rather than yes we show it for Python 3 as well.

Would that take care of your concern?

[MaxSchambach]

Great, I agree! I'm also more in favor of the last two points as the system's Python version is not really relevant for most developers using pyenv/virtualenv or conda to never actually touch the system one. Showing the version of Python 2 makes sense (though not many people will likely be using it) and adding a verbose option to theme_display_virtualenv indeed seems more tidy as opposed to introducing another option in order to have it all in one place.

I'll give it a shot and update the PR 🚀

[MaxSchambach]

Ready from my side, @bobthecow :)