Change return type of registerNodeClass to true (#12960)

Author: ndossche

UPGRADING

@@ -205,6 +205,10 @@ PHP 8.4 UPGRADE NOTES
 5. Changed Functions
 ========================================
 
+- 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.
+
 - Intl:
   . IntlDateFormatter::__construct() throws a ValueError if the locale is invalid.
   . NumberFormatter::__construct() throws a ValueError if the locale is invalid.

ext/dom/php_dom.stub.php

@@ -1098,7 +1098,7 @@ public function importNode(Node $node, bool $deep = false) {}
         public function normalizeDocument(): void {}
 
         /** @tentative-return-type */
-        public function registerNodeClass(string $baseClass, ?string $extendedClass): bool {}
+        public function registerNodeClass(string $baseClass, ?string $extendedClass): true {}
 
 #ifdef LIBXML_SCHEMAS_ENABLED
         /** @tentative-return-type */