Improve fish 4.0 shell support

[zaytsev]

Patches from the mailing list:

v1:

• ​https://lists.midnight-commander.org/pipermail/mc-devel/2024-October/011234.html
• ​https://lists.midnight-commander.org/pipermail/mc-devel/2024-October/011235.html

v2:

• ​https://lists.midnight-commander.org/pipermail/mc-devel/2024-October/011238.html
• ​https://lists.midnight-commander.org/pipermail/mc-devel/2024-October/011239.html
• ​https://lists.midnight-commander.org/pipermail/mc-devel/2024-October/011240.html

[zaytsev]

Yes, I don't like the environment variable thing all... Is it possible for fish to parse our version from mc --version? If this is not practical, maybe we could consider exporting a generic MC_VERSION variable?

[johannes]

I just sent an updated patch series to the mailing list,
to use MC_VERSION instead.
That third patch is not absolutely necessary but it would be nice, to allow users to converge quicklier on the new keyboard input style.

Let me know if there is anything else for me to do; I realize I didn't add a changelog entry; not sure if that's necessary.

[zaytsev]

Could you please just attach them here (git format-patch HEAD~~)? I'm not sure if there are any differences otherwise and it's really painful to save messages and upload. I will remove my first comment.