ext/standard: declare true as the return type of register_tick_function()

UPGRADING

@@ -618,6 +618,9 @@ PHP 8.6 UPGRADE NOTES
   . header_register_callback() now declares true as its return type. It has not
     been able to return false since PHP 8.0.0, where passing an invalid
     callback started throwing a TypeError instead.
+  . register_tick_function() now declares true as its return type. It has
+    always returned true on success; an invalid callback throws a TypeError
+    via ZPP before the function body is reached.
   . ini_get_all() now includes a "builtin_default_value" element for each
     directive when $details is true. It holds the built-in default value of the
     directive (or null if it has none), independent of values set in php.ini,

ext/standard/basic_functions.stub.php

@@ -2063,7 +2063,7 @@ function getprotobyname(string $protocol): int|false {}
 function getprotobynumber(int $protocol): string|false {}
 #endif
 
-function register_tick_function(callable $callback, mixed ...$args): bool {}
+function register_tick_function(callable $callback, mixed ...$args): true {}
 
 function unregister_tick_function(callable $callback): void {}