Hello,

This patch updates fish to the latest released version (2023-01-07) as
it seems to work well (it's my main shell and I have been testing this
version on Guix on a daily basis this week).

The update was made with guix refresh and then tested on a daily basis
during this week (only on x86_64 architecture though, as I wanted to
make a first patch before struggling with virtualisation).

We have to remove PCRE2 related snippets as upstream removed the bundled
copy from its source[1] (see “For Distributors” header).

In the near future, we'll probably need to change the build system and
the package definition a lot, as Fish is being rewritten in rust[2].

Given the nature of this patch, I don't care being credited in the
copyright notice.

PS: This is my first patch, I hope I'm properly following the
conventions, please tell me if I can do anything better next times :)

[1] https://github.com/fish-shell/fish-shell/releases/tag/3.6.0
[2] https://github.com/fish-shell/fish-shell/pull/9512