Remove spurious return true from DOMXPath::registerPhpFunctions()

Only one of three identical cases returned true, and the function
is documented to return void. Remove the outlier.

Author: nikic

ext/dom/php_dom.stub.php

@@ -425,7 +425,7 @@ public function query(string $expr, ?DOMNode $context = null, bool $registerNode
     /** @return bool */
     public function registerNamespace(string $prefix, string $namespaceURI) {}
 
-    /** @return bool|null */
+    /** @return void */
     public function registerPhpFunctions(string|array|null $restrict = null) {}
 }
 #endif

ext/dom/php_dom_arginfo.h

@@ -1,5 +1,5 @@
 /* This is a generated file, edit the .stub.php file instead.
- * Stub hash: a9c30985948768261ea275fdbde598cf9119029e */
+ * Stub hash: a30205758df3a00757ffdfdd0c500b090e022d4f */
 
 ZEND_BEGIN_ARG_WITH_RETURN_OBJ_INFO_EX(arginfo_dom_import_simplexml, 0, 1, DOMElement, 1)
 	ZEND_ARG_TYPE_INFO(0, node, IS_OBJECT, 0)

ext/dom/xpath.c

@@ -510,7 +510,6 @@ PHP_METHOD(DOMXPath, registerPhpFunctions)
 			zend_string_release_ex(str, 0);
 		} ZEND_HASH_FOREACH_END();
 		intern->registerPhpFunctions = 2;
-		RETURN_TRUE;
 	} else if (name) {
 		ZVAL_LONG(&new_string, 1);
 		zend_hash_update(intern->registered_phpfunctions, name, &new_string);