Don't repeat hotkeys on WebAssembly

Just like on the other platforms we don't want the hotkeys to repeat if
the key is held down. On WebAssembly we just need to check the `repeat`
field of the `KeyboardEvent` object.

I also snuck in some other minor improvements.

benches/software_rendering.rs

@@ -26,9 +26,14 @@ cfg_if::cfg_if! {
             make_progress_run_with_splits_opt(&mut timer, &[Some(5.0), None, Some(10.0)]);
 
             let snapshot = timer.snapshot();
-            let state = layout.state(&snapshot);
+            let mut state = layout.state(&snapshot);
             let mut renderer = Renderer::new();
 
+            // Do a single frame beforehand as otherwise the layout state will
+            // keep saying that the icons changed.
+            renderer.render(&state, [300, 500]);
+            layout.update_state(&mut state, &snapshot);
+
             c.bench_function("Software Rendering (Default)", move |b| {
                 b.iter(|| renderer.render(&state, [300, 500]))
             });
@@ -43,9 +48,14 @@ cfg_if::cfg_if! {
             make_progress_run_with_splits_opt(&mut timer, &[Some(10.0), None, Some(20.0), Some(55.0)]);
 
             let snapshot = timer.snapshot();
-            let state = layout.state(&snapshot);
+            let mut state = layout.state(&snapshot);
             let mut renderer = Renderer::new();
 
+            // Do a single frame beforehand as otherwise the layout state will
+            // keep saying that the icons changed.
+            renderer.render(&state, [300, 800]);
+            layout.update_state(&mut state, &snapshot);
+
             c.bench_function("Software Rendering (Subsplits Layout)", move |b| {
                 b.iter(|| renderer.render(&state, [300, 800]))
             });

crates/livesplit-hotkey/src/wasm_web/mod.rs

@@ -73,9 +73,11 @@ impl Hook {
 
         let hotkey_map = hotkeys.clone();
         let keyboard_callback = Closure::wrap(Box::new(move |event: KeyboardEvent| {
-            if let Ok(code) = event.code().parse() {
-                if let Some(callback) = hotkey_map.lock().unwrap().get_mut(&code) {
-                    callback();
+            if !event.repeat() {
+                if let Ok(code) = event.code().parse() {
+                    if let Some(callback) = hotkey_map.lock().unwrap().get_mut(&code) {
+                        callback();
+                    }
                 }
             }
         }) as Box<dyn FnMut(KeyboardEvent)>);

crates/livesplit-hotkey/src/windows/mod.rs

@@ -63,6 +63,8 @@ thread_local! {
 }
 
 fn parse_scan_code(value: DWORD) -> Option<KeyCode> {
+    // Windows uses PS/2 scan code set 1.
+    // https://www.avrfreaks.net/sites/default/files/PS2%20Keyboard.pdf Page 19
     use self::KeyCode::*;
     Some(match value {
         0x0001 => Escape,