Follow-up on GH-13516: include config.h from build dir for new files in ext-dom (#14705)

GH-13516 was created before the new DOM files were added, and the PR was
never rebased to include the new DOM files, so there are three places
which were not replaced.

Author: nielsdos

ext/dom/html_collection.c

@@ -15,7 +15,7 @@
 */
 
 #ifdef HAVE_CONFIG_H
-#include "config.h"
+#include <config.h>
 #endif
 
 #include "php.h"

ext/dom/infra.c

@@ -15,7 +15,7 @@
 */
 
 #ifdef HAVE_CONFIG_H
-#include "config.h"
+#include <config.h>
 #endif
 
 #include "php.h"

ext/dom/xml_serializer.c

@@ -15,7 +15,7 @@
 */
 
 #ifdef HAVE_CONFIG_H
-#include "config.h"
+#include <config.h>
 #endif
 
 #include "php.h"