winit-core:winit: add tablet input support

The API is integrated into the `WindowEvent::Pointer*` API and is
present in form of `TabletTool` variant on corresponding data entries.

For now implemented for Web, Windows, and with limitations for Wayland.

Fixes #99.

Author: daxpedda

clippy.toml

@@ -10,6 +10,9 @@ disallowed-methods = [
     { allow-invalid = true, path = "web_sys::HtmlCanvasElement::set_width", reason = "Winit shouldn't touch the internal canvas size" },
     { allow-invalid = true, path = "web_sys::HtmlCanvasElement::width", reason = "Winit shouldn't touch the internal canvas size" },
     { allow-invalid = true, path = "web_sys::HtmlElement::style", reason = "cache this to reduce calls to JS" },
+    { allow-invalid = true, path = "web_sys::MouseEvent::buttons", reason = "Use `backend::event::cursor_buttons()` to avoid wrong conversions" },
+    { allow-invalid = true, path = "web_sys::MouseEvent::button", reason = "Use `backend::event::cursor_button()` to avoid wrong conversions" },
+    { allow-invalid = true, path = "web_sys::PointerEvent::pointer_type", reason = "Use `WebPointerType` to emit warnings" },
     { allow-invalid = true, path = "web_sys::Window::document", reason = "cache this to reduce calls to JS" },
     { allow-invalid = true, path = "web_sys::Window::get_computed_style", reason = "cache this to reduce calls to JS" },
     { allow-invalid = true, path = "web_sys::Window::navigator", reason = "cache this to reduce calls to JS" },