Add a button to change theme on the main page?

[GuillaumeGomez]

Currently, it's only possible to change the theme from the documentation pages. Adding a button on the "main" page (/) would improve this situation.

[Nemo157]

One downside of doing this is that rustdoc has more than just "change the theme", it by default (since very recently) does system colorscheme detection and switches between light and dark, and allows you to configure which themes to use for light/dark. Replicating this whole system and keeping it integrated well with rustdoc seems complicated.