python3-sphinx: backport patch to fix singlehtml URIs

python3-sphinx: backport patch to fix singlehtml URIs

The singlehtml builder creates broken links, as reported on the
yocto-docs list[1].

This issue was also reported upstream[2], and the temporary fix is to
revert commit c93723b80396 ("singlehtml: deprecate the 'fix_refuris'
helper function (#13037)") in sphinx.

Backport the revert commit as a patch in OE-Core.

[1]: https://lore.kernel.org/r/d8d48a98-edb6-4e30-a49b-0a9b52b14216@bytesatwork.ch
[2]: https://github.com/sphinx-doc/sphinx/issues/14221

Signed-off-by: Antonin Godard <antonin.godard@bootlin.com>
Signed-off-by: Mathieu Dubois-Briand <mathieu.dubois-briand@bootlin.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>