Option to update URL with `?lang=` when selecting a language on the widget UI

[majal]

URL-Based Language Switching is nice.

Can we further advance the functionality by adding the ?lang= parameter when a user chooses a language to translate to? This may be made as an optional choice.

The benefit is, when a user reads the website in a certain language and they want to share it, they will copy the URL. The more common expectation is, that the shared site will be in the same language as the one being read by the user. But most people does not even know what a search param is. So if we provide it to them, they will be able to share according to their expectation and intent.