I have a dream where someone writes a processor that will allow the writer to bang out some Markdown-ish plaintext and turn it into a p&a with automatically generated Table of Contents, Table of Authorities, caption, and pleading paper.

Call it LexDown or something even less mellifluous and free millions from the tyranny of Word style sheets forever.

I was curious and searched if there was a project of that name already: https://github.com/OpenIus/lexdown

You may be interested in Markua https://leanpub.com/markua/read

As far as I'm aware, the vast majority of legal documents are still written with Word or Google Docs. Nearly everybody went to Word when WordPerfect died.