Moved the MakeURLRequestError error from the MakeURLRequestUseCase use case to its own file.

Sources/Communications/Errors/MakeURLRequestError.swift

@@ -0,0 +1,17 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the SwiftLibs open source project
+//
+// Copyright (c) 2023 Röck+Cöde VoF. and the SwiftLibs project authors
+// Licensed under the EUPL 1.2 or later.
+//
+// See LICENSE.txt for license information
+// See CONTRIBUTORS.txt for the list of SwiftLibs project authors
+//
+//===----------------------------------------------------------------------===//
+
+/// Errors generated out of the `MakeURLRequestUseCase` use case.
+public enum MakeURLRequestError: Error {
+    /// An expected URL was not created.
+    case urlNotCreated
+}

Sources/Communications/Use Cases/MakeURLRequestUseCase.swift

@@ -49,10 +49,3 @@ public struct MakeURLRequestUseCase {
     }
 
 }
-
-// MARK: - Errors
-
-enum MakeURLRequestError: Error {
-    case urlNotCreated
-}
-