windows: Fix keystroke & keymap (#36572)

Closes #36300

This PR follows Windows conventions by introducing
`KeybindingKeystroke`, so shortcuts now show up as `ctrl-shift-4`
instead of `ctrl-$`.

It also fixes issues with keyboard layouts: when `use_key_equivalents`
is set to true, keys are remapped based on their virtual key codes. For
example, `ctrl-\` on a standard English layout will be mapped to
`ctrl-ё` on a Russian layout.


Release Notes:

- N/A

---------

Co-authored-by: Kate <kate@zed.dev>

crates/gpui/src/platform/test/platform.rs

@@ -1,8 +1,9 @@
 use crate::{
     AnyWindowHandle, BackgroundExecutor, ClipboardItem, CursorStyle, DevicePixels,
-    ForegroundExecutor, Keymap, NoopTextSystem, Platform, PlatformDisplay, PlatformKeyboardLayout,
-    PlatformTextSystem, PromptButton, ScreenCaptureFrame, ScreenCaptureSource, ScreenCaptureStream,
-    SourceMetadata, Task, TestDisplay, TestWindow, WindowAppearance, WindowParams, size,
+    DummyKeyboardMapper, ForegroundExecutor, Keymap, NoopTextSystem, Platform, PlatformDisplay,
+    PlatformKeyboardLayout, PlatformKeyboardMapper, PlatformTextSystem, PromptButton,
+    ScreenCaptureFrame, ScreenCaptureSource, ScreenCaptureStream, SourceMetadata, Task,
+    TestDisplay, TestWindow, WindowAppearance, WindowParams, size,
 };
 use anyhow::Result;
 use collections::VecDeque;
@@ -237,6 +238,10 @@ impl Platform for TestPlatform {
         Box::new(TestKeyboardLayout)
     }
 
+    fn keyboard_mapper(&self) -> Rc<dyn PlatformKeyboardMapper> {
+        Rc::new(DummyKeyboardMapper)
+    }
+
     fn on_keyboard_layout_change(&self, _: Box<dyn FnMut()>) {}
 
     fn run(&self, _on_finish_launching: Box<dyn FnOnce()>) {