message: add function to base Client class
diff: @@ -61,6 +61,8 @@ export interface Client
  getPlugins(options?: GetPluginsOptions): readonly PluginRegistration<Uri>[];
  + getPlugin(options?: GetPluginOptions): PluginRegistration<Uri>;
  +
  getInterfaces(
  options?: GetInterfacesOptions
  ): readonly InterfaceImplementations<Uri>[];
  