feature: use F1 to quick open the Keyboard Shortcuts Reference dialog (#1225)

Signed-off-by: leo <longshuang@msn.cn>

Author: love-linger

src/App.axaml

@@ -35,7 +35,7 @@
   <NativeMenu.Menu>
     <NativeMenu>
       <NativeMenuItem Header="{DynamicResource Text.About.Menu}" Command="{x:Static s:App.OpenAboutCommand}"/>
-      <NativeMenuItem Header="{DynamicResource Text.Hotkeys}" Command="{x:Static s:App.OpenHotkeysCommand}"/>
+      <NativeMenuItem Header="{DynamicResource Text.Hotkeys}" Command="{x:Static s:App.OpenHotkeysCommand}" Gesture="F1"/>
       <NativeMenuItem Header="{DynamicResource Text.SelfUpdate}" Command="{x:Static s:App.CheckForUpdateCommand}" IsVisible="{x:Static s:App.IsCheckForUpdateCommandVisible}"/>
       <NativeMenuItemSeparator/>
       <NativeMenuItem Header="{DynamicResource Text.Preferences}" Command="{x:Static s:App.OpenPreferencesCommand}" Gesture="⌘+,"/>

src/Views/Hotkeys.axaml.cs

@@ -1,3 +1,5 @@
+using Avalonia.Input;
+
 namespace SourceGit.Views
 {
     public partial class Hotkeys : ChromelessWindow
@@ -6,5 +8,13 @@ public Hotkeys()
         {
             InitializeComponent();
         }
+
+        protected override void OnKeyDown(KeyEventArgs e)
+        {
+            base.OnKeyDown(e);
+
+            if (!e.Handled && e.Key == Key.Escape)
+                Close();
+        }
     }
 }

src/Views/Launcher.axaml.cs

@@ -141,6 +141,13 @@ protected override void OnKeyDown(KeyEventArgs e)
                 return;
             }
 
+            // F1 opens preference dialog (macOS use hotkeys in system menu bar)
+            if (!OperatingSystem.IsMacOS() && e.Key == Key.F1)
+            {
+                App.ShowWindow(new Hotkeys(), true);
+                return;
+            }
+
             // Ctrl+Q quits the application (macOS use hotkeys in system menu bar)
             if (!OperatingSystem.IsMacOS() && e.KeyModifiers == KeyModifiers.Control && e.Key == Key.Q)
             {