Returns whether a particular user has the specified capability.

This function also accepts an ID of an object to check against if the capability is a meta capability. Meta
capabilities such as `edit_post` and `edit_user` are capabilities used by the `map_meta_cap()` function to
map to primitive capabilities that a user or role has, such as `edit_posts` and `edit_others_posts`.

Example usage:

user_can( $user->ID, ‘edit_posts’ );
user_can( $user->ID, ‘edit_post’, $post->ID );
user_can( $user->ID, ‘edit_post_meta’, $post->ID, $meta_key );

function user_can( $user, $capability, ...$args ) {
	if ( ! is_object( $user ) ) {
		$user = get_userdata( $user );
	}

	if ( empty( $user ) ) {
		// User is logged out, create anonymous user object.
		$user = new WP_User( 0 );
		$user->init( new stdClass );
	}

	return $user->has_cap( $capability, ...$args );
}