Add documentation about less invasive installation method

[ShalokShalom]

Question

The Arch Wiki for the fish shell offers a less invasive approach, to use the shell:

I suggest to include that method

Additional context and details

I would do it myself, if that is welcome :sligh

[fdncred]

One difference between fish-shell and nushell is that nushell is cross-platform, fish-shell is not. So, while these instructions may work for Linux or MacOS, it doesn't exactly work on Windows for several reasons.

[devyn]

One option that does generally work on all platforms is to suggest changing the default shell command of the terminal emulator. This is what I personally do, and it's what we suggest first here.

[ShalokShalom]

The question is, if that supports bash scripts as well, as a backwards compatibility option. And yes, the Windows issue should be mentioned, apparently.