Strange workbench contrib `src/vs/workbench/contrib/xdg_data/fish`

[bpasero]

(I think from #168211)

I came across src/vs/workbench/contrib/xdg_data/fish/vendor_conf.d/vscode-shell-integration.fish and fail to understand why it was put there. workbench/contrib is for code contributions that enrich the workbench experience but not for loose files.

Can we move this into the terminal contribution land?