Docs: Replace incorrect @private tags.

The `@private` tag does not exist and is not supported. To indicate that something is private when in the global namespace, `@access private` should be used instead.

Reference: [https://developer.wordpress.org/coding-standards/inline-documentation-standards/php/#phpdoc-tags PHP Documentation Standards: PHPDoc tags].

Props jrf.
See #59651.

git-svn-id: https://develop.svn.wordpress.org/trunk@57065 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-includes/blocks.php

@@ -1197,8 +1197,8 @@ function filter_block_content( $text, $allowed_html = 'post', $allowed_protocols
 /**
  * Callback used for regular expression replacement in filter_block_content().
  *
- * @private
  * @since 6.2.1
+ * @access private
  *
  * @param array $matches Array of preg_replace_callback matches.
  * @return string Replacement string.