A CLI for publishing standard.site documents to ATProto sequoia.pub

Remove strikethrough, comments, and footnotes from `textContent` #170

Merged jack.is
targeting main from jack.is/sequoia:remove-additional-markdown
Merged opened by and assigned to jack.is
targeting main from jack.is/sequoia:remove-additional-markdown

Fixes #36.

Commits 2

Handle 1 or 2 tildes using backreference
Remove strikethrough, comments, and footnotes from `textContent`