Registers a block type. The recommended way is to register a block type using
the metadata stored in the `block.json` file.

function register_block_type( $block_type, $args = array() ) {
	if ( is_string( $block_type ) && file_exists( $block_type ) ) {
		return register_block_type_from_metadata( $block_type, $args );
	}

	return WP_Block_Type_Registry::get_instance()->register( $block_type, $args );
}