[Emulator] Launch file based on signature instead of file extension

src/xenia/app/emulator_window.h

@@ -228,6 +228,9 @@ class EmulatorWindow {
   bool IsUseNexusForGameBarEnabled();
   void DisplayHotKeysConfig();
 
+  static std::string CanonicalizeFileExtension(
+      const std::filesystem::path& path);
+
   void RunPreviouslyPlayedTitle();
   void FillRecentlyLaunchedTitlesMenu(xe::ui::MenuItem* recent_menu);
   void LoadRecentlyLaunchedTitles();