[xonsh] Add 'xdg_configuration_files'

[wy-z]

Signed-off-by: weiyang [email protected]

According to the official documentation, Xonsh also supports with the XDG Base Directory Specification.
https://xon.sh/xonshrc.html

Xonsh also allows a per-user run control file in your home directory, either directly in the home directory at ~/.xonshrc or, for XDG compliance, at ~/.config/xonsh/rc.xsh. The options set per user override settings in the system-wide control file.

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