West patch lacks documentation

[matt-wood-ct]

Is your enhancement proposal related to a problem? Please describe.
There is no documentation beyond the CLI help for west patch, my team have been actively using zephyr for years and none of us noticed this feature even existed until today.
If we had known about it we would have had a much easier time handling WIP driver fixes, we previously took the whole drivers out of tree to tweak them while PRs were going through.

IMO This seems like a very good and very important feature, it deserves to be fully explained to users. The linking to PRs seems especially interesting.

Describe the solution you'd like
It would be nice to have a page or section in the west built-in commands documentation.

Describe alternatives you've considered
N/A

Additional context
Currently the best source on how to use this excellent feature is the discussion in the PR and the yaml schema file.

[pdgendt]

This isn't a west built-in command, but a Zephyr extension and this can/should be added at https://github.com/zephyrproject-rtos/zephyr/blob/4d848ebdb1148794189661b7e5741c0f96ee22b8/doc/develop/west/zephyr-cmds.rst

[cfriedt]

I wish I understood the link-to-pr feature better. Perhaps the documentation can be updated collaboratively?

[cfriedt]

I just went through west patch gh-fetch. It's ok.

It would be nice to be able to refer to a pull request inside the YAML directly as well, so that west patch apply would download, verify, and apply a patch series from a given PR.