Editor: Ensure block style name does not contain spaces before creating the class.

This change adds a check to ensure there is no spaces in block style variation names before generating the class. Returns `false` and a `_doing_it_wrong()` message if a space is detected.

Props amustaque97, costdev, hellofromtonya, pbiron, SergeyBiryukov, afragen.
Fixes #54296.

Built from https://develop.svn.wordpress.org/trunk@52261


git-svn-id: http://core.svn.wordpress.org/trunk@51853 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/class-wp-block-styles-registry.php

@@ -62,6 +62,15 @@ final class WP_Block_Styles_Registry {
 			return false;
 		}
 
+		if ( str_contains( $style_properties['name'], ' ' ) ) {
+			_doing_it_wrong(
+				__METHOD__,
+				__( 'Block style name must not contain any spaces.' ),
+				'5.9.0'
+			);
+			return false;
+		}
+
 		$block_style_name = $style_properties['name'];
 
 		if ( ! isset( $this->registered_block_styles[ $block_name ] ) ) {

wp-includes/version.php

@@ -16,7 +16,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '5.9-alpha-52260';
+$wp_version = '5.9-alpha-52261';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.