api: overhaul pointer API

- Rename `CursorMoved` to `PointerMoved`.
- Rename `CursorEntered` to `PointerEntered`.
- Rename `CursorLeft` to `PointerLeft`.
- Rename `MouseInput` to `PointerButton`.
- Add `position` to every `PointerEvent`.
- Remove `Touch`, which is folded into the `Pointer*` events.
- New `PointerType` added to `PointerEntered` and `PointerLeft`,
  signifying which pointer type is the source of this event.
- New `PointerSource` added to `PointerMoved`, similar to `PointerType`
  but holding additional data.
- New `ButtonSource` added to `PointerButton`, similar to `PointerType`
  but holding pointer type specific buttons. Use
  `ButtonSource::mouse_button()` to easily normalize any pointer button
  type to a generic mouse button.
- In the same spirit rename `DeviceEvent::MouseMotion` to `PointerMotion`.
- Remove `Force::Calibrated::altitude_angle`.

Fixes #3833.
Fixes #883.
Fixes #336.

Co-authored-by: Kirill Chibisov <contact@kchibisov.com>

src/platform_impl/linux/common/xkb/keymap.rs

@@ -638,7 +638,7 @@ pub fn keysym_to_key(keysym: u32) -> Key {
         // keysyms::ISO_Release_Margin_Left => NamedKey::IsoReleaseMarginLeft,
         // keysyms::ISO_Release_Margin_Right => NamedKey::IsoReleaseMarginRight,
         // keysyms::ISO_Release_Both_Margins => NamedKey::IsoReleaseBothMargins,
-        // keysyms::ISO_Fast_Cursor_Left => NamedKey::IsoFastCursorLeft,
+        // keysyms::ISO_Fast_Cursor_Left => NamedKey::IsoFastPointerLeft,
         // keysyms::ISO_Fast_Cursor_Right => NamedKey::IsoFastCursorRight,
         // keysyms::ISO_Fast_Cursor_Up => NamedKey::IsoFastCursorUp,
         // keysyms::ISO_Fast_Cursor_Down => NamedKey::IsoFastCursorDown,