Make return type of trigger_error() and user_error() true (#13169)

Author: nielsdos

UPGRADING

@@ -267,6 +267,10 @@ PDO_SQLITE:
 5. Changed Functions
 ========================================
 
+- Core:
+  . trigger_error() and user_error() now have a return type of true instead of
+    bool.
+
 - DOM:
   . DOMDocument::registerNodeClass() now has a tentative return type of true.
     Previously, the return type was bool but only true could be returned in practice.

Zend/zend_builtin_functions.stub.php

@@ -95,10 +95,10 @@ function get_included_files(): array {}
  */
 function get_required_files(): array {}
 
-function trigger_error(string $message, int $error_level = E_USER_NOTICE): bool {}
+function trigger_error(string $message, int $error_level = E_USER_NOTICE): true {}
 
 /** @alias trigger_error */
-function user_error(string $message, int $error_level = E_USER_NOTICE): bool {}
+function user_error(string $message, int $error_level = E_USER_NOTICE): true {}
 
 /** @return callable|null */
 function set_error_handler(?callable $callback, int $error_levels = E_ALL) {}