Displays the robots meta tag as necessary.

Gathers robots directives to include for the current context, using the
{@see ‘wp_robots’} filter. The directives are then sanitized, and the
robots meta tag is output if there is at least one relevant directive.

function wp_robots() {
	/**
	 * Filters the directives to be included in the 'robots' meta tag.
	 *
	 * The meta tag will only be included as necessary.
	 *
	 * @since 5.7.0
	 *
	 * @param array $robots Associative array of directives. Every key must be the name of the directive, and the
	 *                      corresponding value must either be a string to provide as value for the directive or a
	 *                      boolean `true` if it is a boolean directive, i.e. without a value.
	 */
	$robots = apply_filters( 'wp_robots', array() );

	$robots_strings = array();
	foreach ( $robots as $directive => $value ) {
		if ( is_string( $value ) ) {
			// If a string value, include it as value for the directive.
			$robots_strings[] = "{$directive}:{$value}";
		} elseif ( $value ) {
			// Otherwise, include the directive if it is truthy.
			$robots_strings[] = $directive;
		}
	}

	if ( empty( $robots_strings ) ) {
		return;
	}

	echo "n";
}