add lua formatter

[lamchau]

This PR adds stylua as an alternative formatter for Lua.

• adds Stylua to README, corrects missing )
• find/replace formatterfiveone with stylua
• vroom has been archived and was unable to get it to build on an M3 MBP but took inspiration from black.vroom, should work? I could use some help testing this

Partially addresses #180.

[dbarnett]

I could use some help testing this

Here ya go: dbarnett@4384b26

I'd also suggest you make --stdin-filepath conditional and pass the short name instead of full path, like I did for another formatter here:

vim-codefmt/autoload/codefmt/ruff.vim

Lines 23 to 25 in e0e113e

	if !empty(@%)
	let l:cmd += ['--stdin-filename=' . @%]
	endif

. Pretty sure formatters don't need or want the full absolute path.

And vroom is unarchived now FWIW.