Register a new document.

        :param content: Content of this document. Jinja and rst are supported.
        :type content: str
        :param name: Unique name of the document for documentation purposes.
        :param description: Short description of this document

def register(self, name, content, description=None):
        """
        Register a new document.

        :param content: Content of this document. Jinja and rst are supported.
        :type content: str
        :param name: Unique name of the document for documentation purposes.
        :param description: Short description of this document
        """
        return self.__app.documents.register(name, content, self._plugin, description)