docs (easy): Add reference to the Python docs theme gh repo

[Privat33r-dev]

The paragraph should be added in bugs.html

If you find a bug in the theme (HTML / CSS / JavaScript) of the
documentation, please submit a bug report on the `python-doc-theme bug
tracker <https://github.com/python/python-docs-theme>`_.

Originally posted by @JulienPalard in python/python-docs-theme#21 (comment)

Linked PRs

• gh-116932: Add notes on how to report python documentation theme bugs #117989
• [3.12] gh-116932: Add note on how to report python documentation theme bugs (GH-117989) #118031
• gh-116932: Remove redundant NEWS entry #118040
• [3.12] gh-116932: Remove redundant NEWS entry (GH-118040) #118041