[NTOS:OB] Enhancements to NtSetInformationObject() (#9170)

- Simplify the `ObjectHandleFlagInformation` class implementation,
  by directly invoking the `ObSetHandleAttributes()` routine.
  Addendum to commit 02d0bb9dbd (r22228) that implemented the class,
  and to commit 91105c7915 (r61037) that implemented `ObSetHandleAttributes()`.

- Use SAL2 annotations; write Doxygen documentation (based on GPT-5.4
  feedback and https://ntdoc.m417z.com/ntsetinformationobject).

sdk/include/ndk/obfuncs.h

@@ -323,7 +323,7 @@ NTAPI
 NtSetInformationObject(
     _In_ HANDLE ObjectHandle,
     _In_ OBJECT_INFORMATION_CLASS ObjectInformationClass,
-    _In_ PVOID ObjectInformation,
+    _In_reads_bytes_(Length) PVOID ObjectInformation,
     _In_ ULONG Length
 );