Housekeeping fix file header (#227)

Author: ChrisPulman

src/ReactiveUI.SourceGenerators.Roslyn/Diagnostics/Suppressions/ReactiveAttributeWithFieldTargetDiagnosticSuppressor.cs

@@ -1,6 +1,6 @@
-// Copyright (c) 2024 .NET Foundation and Contributors. All rights reserved.
-// Licensed to the .NET Foundation under one or more agreements.
-// The .NET Foundation licenses this file to you under the MIT license.
+// Copyright (c) 2025 ReactiveUI and contributors. All rights reserved.
+// Licensed to the ReactiveUI and contributors under one or more agreements.
+// The ReactiveUI and contributors licenses this file to you under the MIT license.
 // See the LICENSE file in the project root for full license information.
 
 using System.Collections.Immutable;