Fix test failure and update spec.

docs/features/nullable-reference-types.md

@@ -211,7 +211,7 @@ var y = F1(maybeNullString); // List<string?> or List<string~> ?
 var z = F2(obliviousString); // List<string~>! or List<string!>! ?
 var w = F3(obliviousString); // List<string~>! or List<string?>! ?
 ```
-A warning is reported for accessing variables of type T, where T is an unconstrained type parameter.
+A warning is reported for dereferencing variables of type T, where T is an unconstrained type parameter.
 ```C#
 static void F<T>(T t) => t.ToString(); // Warn possible null dereference
 ```

src/Compilers/CSharp/Test/Semantic/Semantics/NullableReferenceTypesTests.cs

@@ -36346,9 +36346,9 @@ static void M<U>(U u)
             var comp = CreateCompilation(new[] { source, NonNullTypesAttributesDefinition, NonNullTypesTrue }, parseOptions: TestOptions.Regular8);
             // PROTOTYPE(NullableReferenceTypes): We should warn on the first 3 ToString calls.
             comp.VerifyDiagnostics(
-                // (19,9): error CS0411: The type arguments for method 'C.CopyOutInherit<T1, T2>(T1, out T2)' cannot be inferred from the usage. Try specifying the type arguments explicitly.
-                //         CopyOutInherit(u, out var x4);
-                Diagnostic(ErrorCode.ERR_CantInferMethTypeArgs, "CopyOutInherit").WithArguments("C.CopyOutInherit<T1, T2>(T1, out T2)").WithLocation(19, 9)
+                // (29,9): error CS0411: The type arguments for method 'C.CopyOutInherit<T1, T2>(T1, out T2)' cannot be inferred from the usage. Try specifying the type arguments explicitly.
+                //         CopyOutInherit(u, out var x7);
+                Diagnostic(ErrorCode.ERR_CantInferMethTypeArgs, "CopyOutInherit").WithArguments("C.CopyOutInherit<T1, T2>(T1, out T2)").WithLocation(29, 9)
             );
         }