macOS: Add Open with kitty Service

There are still some file types that cannot be matched.
Add a standalone Open With service.
Users can configure shortcut for this service in System Preferences.

setup.py

@@ -1090,6 +1090,12 @@ def macos_info_plist() -> bytes:
             'NSRequiredContext': {'NSTextContent': 'FilePath'},
             'NSSendTypes': ['NSFilenamesPboardType', 'public.plain-text'],
         },
+        {
+            'NSMenuItem': {'default': f'Open with {appname}'},
+            'NSMessage': 'openFileURLs',
+            'NSRequiredContext': {'NSTextContent': 'FilePath'},
+            'NSSendTypes': ['NSFilenamesPboardType', 'public.plain-text'],
+        },
     ]
 
     pl = dict(