Add "sidebar-theme" in Shell Top-level parameters

[Ajotah98]

Hi,

Currently, the documentation of shell component only states about sidebar:

But when the sidebar component was created, we have included a "sidebar-theme" for letting people have "both" theme websites:

I guess the card with the info should be something like:

sidebar-theme (Boolean, optional)

When used with the "sidebar" propery, it enables the dark theme only on the sidebar.

[lovasoa]

Oh, I missed that! Could we use the global theme by default, make this accept the same values as the theme parameter (instead of being a boolean), and use an underscore in the name?

For the documentation, can you please open a pull request?

[lovasoa]

I'm open to a new pr to add a separate, documented, sidebar_theme, which falls back to the main theme when not specified :)

[Ajotah98]

Mmmm, I didn't put the sidebar-theme to fallback into the main theme! Instead, what I wanted is the possibility to have the sidebar in dark theme and the rest of the app in light theme.

Before the change, the behaviour was:
if not sidebar-theme -> sidebar light, app light
if theme (global) -> sidebar dark, also app dark
if sidebar-theme (but not theme = dark) -> sidebar dark, app light

What do you think about?

[lovasoa]

Ok, that's okay for me. But let's name it sidebar_theme (snake case), and have people set it to "dark", not any truthy value. Can you make a PR with the changes to the code and the docs?