remove unused

src/ytdl_sub/config/plugin/plugin_mapping.py

@@ -217,14 +217,3 @@ class PluginMapping:
                 f"{', '.join(cls.plugins())}"
             )
         return cls._MAPPING[plugin]
-
-    @classmethod
-    def name_of(cls, plugin_options: OptionsValidator) -> str:
-        """
-        Returns plugin definition's name.
-        """
-        for name, plugin_type in cls._MAPPING.items():
-            if plugin_type.plugin_options_type == plugin_options.__class__:
-                return name
-
-        raise ValueError("Plugin name does not exist")