Kernel: Add an x86 include check+error in x86/PageFault.h

Author: https://github.com/jamesmintram
Commit: eb33df0c30
Pull-request: https://github.com/SerenityOS/serenity/pull/11141
Reviewed-by: https://github.com/bgianfo ✅
Reviewed-by: https://github.com/kleinesfilmroellchen ✅

Kernel/Memory/Region.cpp

@@ -6,6 +6,7 @@
 
 #include <AK/Memory.h>
 #include <AK/StringView.h>
+#include <Kernel/Arch/x86/PageFault.h>
 #include <Kernel/Debug.h>
 #include <Kernel/FileSystem/Inode.h>
 #include <Kernel/Memory/AnonymousVMObject.h>