fixes documentation

Author: lightsprint09

Source/URLRequest+Init.swift

@@ -31,7 +31,7 @@ extension URLRequest {
     ///   - path: path to the resource.
     ///   - baseURL: the base url of the resource.
     ///   - HTTPMethod: the HTTP method for the request. Defaults to `.GET`
-    ///   - parameters: url parameters for the request. Defaults to empty dictionary
+    ///   - parameters: url parameters for the request. Defaults to `nil`
     ///   - body: body data payload. Defaults to `nil`
     ///   - allHTTPHeaderFields: HTTP request header fields. Defaults to `nil`
     ///