Co-authored-by: Simon Hausmann <simon.hausmann@slint-ui.com>

... due to rust-skia bindings requiring a feature (ffi related).

- re-order the ChangedSection by "impact"
- Add missing periods.
- For the element highlight, explain when a highlight is shown.
- Elaborate on some entries.

For `Key` this is a move, as it is a new type. For `WindowEvent` and `PointerEventButton` deprecated aliases
are provided.

This allows specifying font sizes relative to the Window's
default-font-size, similar to CSS rem.

But it still defaults to `in-out`

This enables imperative code to be run. To be used sparingly :-)

This change adds `KeyPress` and `KeyRelease` variants to the
`WindowEvent` enum, along with the new `slint::Key` enum, that allows
encoding keys.

The test was only failing in some cases with node because of the
inlining in the interpreter, and it depended in which order the property
were processed (they were in a hash)

A test property was added to also test the interpreter

Add material, material-light and material-dark widgets and make it available by the `env` `SLINT_STYLE`.

previous commit added its entry in the wrong section

- Complete sentences
- Re-order a little
- Add version and release date

These variants of the fluent style will use either the light or the dark color scheme,
regardless of the system wide setting.

CC #1678  #1647

* Add a C++ Map Model class

This matches the MapModel in the Rust API.

Add a C++ Filter Model class

This matches the FilterModel in the Rust API.

End sentences with a period, so that entries that have two sentences look the same as entries with just one.

as discussed on Mattermost a few days ago

Co-authored-by: Simon Hausmann <simon.hausmann@slint-ui.com>

Fixes #1221