ext/standard: change print_r return type from string|bool to string|true

Author: Ayesh

UPGRADING

@@ -566,6 +566,7 @@ PHP 8.4 UPGRADE NOTES
   . 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.
+  . print_r() now has a return type of string|true instead of string|bool.
 
 ========================================
 6. New Functions

ext/standard/basic_functions.stub.php

@@ -2050,7 +2050,7 @@ function set_include_path(string $include_path): string|false {}
 function get_include_path(): string|false {}
 
 /** @refcount 1 */
-function print_r(mixed $value, bool $return = false): string|bool {}
+function print_r(mixed $value, bool $return = false): string|true {}
 
 function connection_aborted(): int {}