[DOC] Dark theme is missing for non-English languages

[adorilson]

Documentation

Open the Docs
Change theme to Dark (it's work)
Change the language to, e.g, Brazilian Portuguese. (it backed to Ligth theme)

[AA-Turner]

Duplicate of #229, we're running rebuilds.

[AA-Turner]

@adorilson the full rebuild has now finished (it takes several hours). https://docs.python.org/pt-br/3/ has dark-mode support for me.