Comments: Make `wp_required_field_indicator()` and `wp_required_field_message()` output filterable.

This changeset introduces two new hooks:

- `wp_required_field_indicator` allows developers to filter the HTML output of the `wp_required_field_indicator()` function.
- `wp_required_field_message` does the same for the `wp_required_field_message()` function.

The changeset also adds new phpunit tests for these filters.

Follow-up to [53888], [54136].

Props kebbet, audrasjb, sabernhardt, costdev, mukesh27.
Fixes #56389.
See #54394.

Built from https://develop.svn.wordpress.org/trunk@54137


git-svn-id: http://core.svn.wordpress.org/trunk@53696 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/general-template.php

@@ -5026,7 +5026,14 @@ function wp_required_field_indicator() {
 	$glyph     = __( '*' );
 	$indicator = '<span class="required">' . esc_html( $glyph ) . '</span>';
 
-	return $indicator;
+	/**
+	 * Filters the markup for a visual indicator of required form fields.
+	 *
+	 * @since 6.1.0
+	 *
+	 * @param string $indicator Markup for the indicator element.
+	 */
+	return apply_filters( 'wp_required_field_indicator', $indicator );
 }
 
 /**
@@ -5043,7 +5050,14 @@ function wp_required_field_message() {
 		sprintf( __( 'Required fields are marked %s' ), wp_required_field_indicator() )
 	);
 
-	return $message;
+	/**
+	 * Filters the message to explain required form fields.
+	 *
+	 * @since 6.1.0
+	 *
+	 * @param string $message Message text and glyph wrapped in a `span` tag.
+	 */
+	return apply_filters( 'wp_required_field_message', $message );
 }
 
 /**

wp-includes/version.php

@@ -16,7 +16,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '6.1-alpha-54136';
+$wp_version = '6.1-alpha-54137';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.