Fix comment about nullness boolean.

PiperOrigin-RevId: 487825304
diff --git a/nullability_verification/pointer_nullability.h b/nullability_verification/pointer_nullability.h
index 9b711bd..0762364 100644
--- a/nullability_verification/pointer_nullability.h
+++ b/nullability_verification/pointer_nullability.h
@@ -29,7 +29,7 @@
 /// Returns the properties representing the nullness information of a pointer.
 ///
 /// The first boolean indicates if the pointer's nullability is known.
-/// The second boolean indicates if the pointer's value is not null.
+/// The second boolean indicates if the pointer's value is null.
 std::pair<dataflow::AtomicBoolValue&, dataflow::AtomicBoolValue&>
 getPointerNullState(const dataflow::PointerValue& PointerVal,
                     const dataflow::Environment& Env);