Address Suggestions

Author: denil-ct

Sources/OpenAPIURLSession/Documentation.docc/Documentation.md

@@ -8,6 +8,11 @@ A client transport that uses the [URLSession](https://developer.apple.com/docume
 
 Use the transport with client code generated by [Swift OpenAPI Generator](https://github.com/apple/swift-openapi-generator).
 
+### Supported platforms and minimum versions
+| macOS | Linux | iOS | tvOS | watchOS |
+| :-: | :-: | :-: | :-: | :-: |
+| ✅ 10.15+  | ✅     | ✅ 13+ | ✅ 13+ | ✅ 6+ |
+
 ### Usage
 
 Add the package dependency in your `Package.swift`:

Sources/OpenAPIURLSession/URLSessionTransport.swift

@@ -179,7 +179,7 @@ extension URLSessionTransportError: CustomStringConvertible {
         case .notHTTPResponse(let response):
             return "Received a non-HTTP response, of type: \(String(describing: type(of: response)))"
         case .noResponse(let url):
-            return "Received a nil response for \(url?.absoluteString ?? "")"
+            return "Received a nil response for \(url?.absoluteString ?? "<nil URL>")"
         }
     }
 }