docs: fix lua codes, consistent nerdfonts symbols, formatting

[gepbird]

The last formatting commit 7eb332650221951c5c61adad8f3be6ad2e5a2bcb has a much bigger diff than the other commits, please review commit-by-commit rather than all commits at the same time to make it easier for yourself :)

Let me know if you prefer another style for lua code in docs, I mostly followed the project's stylua.toml with a few exceptions:

• 4 space indent (this was more common than 2 spaces)
• don't merge if statements to one line

[akinsho]

Hi @gepbird,

These appear to be a lot of stylistic changes mixed in with some more important fixes. Can we just address the crucial fixes first in a minimal PR just aimed at those then discuss any style changes as a followup. In general a lot of the attempts to add booleans and things like that are actually contrary to my intentions. The reason I added them like that was actually to specifically discourage copy-pasting which ends up being a huge cause of issues for me since if the code is clearly not copy-pastable people tend to add things in themselves rather than copy a huge blob then complain it doesn't work as they expect

[gepbird]

Sure, I'll break these changes up to multiple PRs.