msys2 path patches to make git functions work at least

[shikorido]

The patch assumes that plenary.nvim has the changes I made in the corresponded PR. At least for plenary.utils module and path conversions in internal logic.

As stated in the plenary's PR the msys2 integration is very fragile so I left all my comments and test notifies for further debugging.

Description

I want to make Plenary and Telescope compliant with msys2 (and windows indirectly).
The good looking changes can be hard to achieve cause msys2 returns posix-style paths but can use Windows-style
and in the same time neovim from clang64 repo returns windows-style paths but can not use posix-style.

The main idea would be a complete dependence on Plenary/Nvim path work.
But now I want to share how the fix-up changes look like in the current version (w/o breaking changes).

The fixes are mainly for git-related functions. I wanted to have it working and I achieved that with dirty changes.

Type of change

• Bug fix (non-breaking change which fixes an issue)

How Has This Been Tested?

The issue is more likely to be long-term, so I will leave the reproduction steps for later
if someone ever wants to reproduce it and doesn't have msys2+nvim configured yet.

• Git bcommits with working diff preview and checkouting (bcommits range was not tested).
• Git branches with working commits history and checkouting.
• Git commits with working diff preview and checkouting.
• Git files with working preview and files selecting.
• Git stash with working diff preview and stash application.
• Git status with working diff/file preview and designations of file status.

Configuration:

• WezTerm: 20240203-110809-5046fc22 (if makes any sense)
• Zsh: 5.9 (x86_64-pc-msys) (maybe causes {} expansion)
• Bash: GNU bash, version 5.2.37(2)-release (x86_64-pc-cygwin) (setted as nvim shell)
• Neovim version (nvim --version): NVIM v0.11.1 from msys2's clang64 repo
• Operating system and version: Windows 10 Pro 22H2 19045.5854

Checklist:

• Deep-draft
• My code follows the style guidelines of this project (stylua)
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation (lua annotations)