ext/standard: change highlight_string() return type from string|bool to string|true

Author: Ayesh

UPGRADING

@@ -565,6 +565,7 @@ PHP 8.4 UPGRADE NOTES
     one digit.
   . output_add_rewrite_var() now uses url_rewriter.hosts instead of
     session.trans_sid_hosts for selecting hosts that will be rewritten.
+  . highlight_string() now has a return type of string|true instead of string|bool.
 
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 6. New Functions

ext/standard/basic_functions.stub.php

@@ -2024,7 +2024,7 @@ function show_source(string $filename, bool $return = false): string|bool {}
 function php_strip_whitespace(string $filename): string {}
 
 /** @refcount 1 */
-function highlight_string(string $string, bool $return = false): string|bool {}
+function highlight_string(string $string, bool $return = false): string|true {}
 
 function ini_get(string $option): string|false {}