style: font fallback for windows

Author: love-linger

src/SourceGit/Native/Windows.cs

@@ -21,6 +21,7 @@ public void SetupApp(AppBuilder builder)
             builder.With(new FontManagerOptions()
             {
                 DefaultFamilyName = "Microsoft YaHei UI",
+                FontFallbacks = [new FontFallback { FontFamily = "Microsoft YaHei" }],
             });
         }