Implement shell integration for xonsh shell

[pltrz]

What do you want to change?

I would like to add built-in support for shell integration for xonsh shell. As seen for bash, zsh, fish, elvish, nushell.

Why do you want to make this change?

Enable these features for users that use xonsh as their primary shell.

I acknowledge that:

• I have read the Contributing Guide and understand the contribution process.
• I have read and agree to follow the AI Usage Policy.
• I wrote this vouch request myself, in my own voice, without AI generating it.

[jcollie]

!vouch

[jcollie]

We'd love to have support for more shells. However, unless there's someone around long-term that can support such integration we may choose to not accept the PR.

[pltrz]

Thanks! Perfectly understandable.