Improve documentation workflow.

[seflue]

Describe the bug

I have two issues with the documentation as it is currently.

1. it is not consistently formatted. In my setup I have enabled automatic reformatting for markdown files and it changes basically the whole file. Having a consistent and commonly used formatting standard would be very helpful, because otherwise it is quite tedious to adjust the documentation. Ideally it would come with a formatting configuration as part of the repository, but I am currently not aware of a solution for markdown.
2. The currently used md2vim to generate the vim help from the markdown files is far from ideal. The generated vimhelp.txt lacks a lot of features which are actually part of vims help system and make the manual unnecessary hard to use. Fortunately, I just stumbled over a very promising looking project, panvimdoc which has all the nice features md2vim is missing. And while md2vim is actually archived, vim-pandoc is actively developed. They provide a ready-to-go github action, so it should not be hard to integrate it in this project.

@kristijanhusak Before I put work into this, I want to ask, if there is motivation to actually go in this direction.

Steps to reproduce

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Expected behavior

1. A consistently formatted set of markdown files for documentation so updating doesn't need cumbersome reconfiguration of the editor or carful selection of actual changes after saving the file.
2. A vimhelp.txt which is actually navigable with the features of vim help, like jumpable tags.

Emacs functionality

No response

Minimal init.lua

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Screenshots and recordings

No response

OS / Distro

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Neovim version/commit

all currently supported versions

Additional context

No response