Add an application wide template filter.

        This is designed to be used as a decorator, and has the same arguments
        as :meth:`~quart.Quart.template_filter`. An example usage,

        .. code-block:: python

            blueprint = Blueprint(__name__)
            @blueprint.app_template_filter()
            def filter(value):
                ...

def app_template_filter(self, name: Optional[str]=None) -> Callable:
        """Add an application wide template filter.

        This is designed to be used as a decorator, and has the same arguments
        as :meth:`~quart.Quart.template_filter`. An example usage,

        .. code-block:: python

            blueprint = Blueprint(__name__)
            @blueprint.app_template_filter()
            def filter(value):
                ...
        """
        def decorator(func: Callable) -> Callable:
            self.add_app_template_filter(func, name=name)
            return func
        return decorator