This PR adds support for configuring both a light and dark theme in
`settings.json`.
In addition to accepting just a theme name, the `theme` field now also
accepts an object in the following form:
```jsonc
{
"theme": {
"mode": "system",
"light": "One Light",
"dark": "One Dark"
}
}
```
Both `light` and `dark` are required, and indicate which theme should be
used when the system is in light mode and dark mode, respectively.
The `mode` field is optional and indicates which theme should be used:
- `"system"` - Use the theme that corresponds to the system's
appearance.
- `"light"` - Use the theme indicated by the `light` field.
- `"dark"` - Use the theme indicated by the `dark` field.
Thank you to @Yesterday17 for taking a first stab at this in #6881!
Release Notes:
- Added support for configuring both a light and dark theme and
switching between them based on system preference.
a80a3b8706