lang/python-doc-html: fix DISTINFO for 2025Q4

Reverts "lang/python-doc-html: strip python 3.9 from distinfo, no longer referenced"

This reverts commit 519164dfc178f37b3f78266b2f5e5a4009d6f5c8.

Reason is that 2025Q4 still has python39, so we need to keep the
relevant distinfo data.