html_to_markdown: Move `TableHandler` out of `rustdoc` (#12697)

This PR moves the `TableHandler` out of the `rustdoc` module, as it
doesn't contain anything specific to rustdoc.

Release Notes:

- N/A

Marshall Bowers committed 2y ago

f3460d440cd6c401b883c279c223c6f18287d22d

Parent: 071270f

Committed by GitHub <noreply@github.com> on 6/5/2024, 7:37:02 PM