Fix broken URIs on "Rendering HTML" Diviner page

Summary: Remove incorrect book scope from numerous find URIs on the "Rendering HTML" Diviner page in order to get results instead of 404 pages.

Test Plan:
Refresh Diviner documentation from Phorge directory:

./bin/diviner generate

Go to https://we.phorge.it/book/contrib/article/rendering_html/ and click random links on that page.

Reviewers: O1 Blessed Committers, valerio.bozzolan

Reviewed By: O1 Blessed Committers, valerio.bozzolan

Subscribers: tobiaswiese, valerio.bozzolan, Matthew, Cigaryno

Differential Revision: https://we.phorge.it/D25688