tools: make internal link checker more robust

The internal link checker was missing some broken links because it was
being too restrictive about the characters it accepted as part of a link
hash. Accept anything that isn't a terminating quotation mark.

Refs: https://github.com/nodejs/node/pull/39426
Refs: https://github.com/nodejs/node/pull/39425

PR-URL: https://github.com/nodejs/node/pull/39429


Reviewed-By: Tobias Nießen <tniessen@tnie.de>
Reviewed-By: Antoine du Hamel <duhamelantoine1995@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Zeyu Yang <himself65@outlook.com>