refactor(http)!: fix cascade dart good practices + docs

packages/wyatt_http_client/lib/src/middleware.dart

@@ -18,12 +18,21 @@ import 'package:wyatt_http_client/src/models/middleware_context.dart';
 import 'package:wyatt_http_client/src/models/middleware_request.dart';
 import 'package:wyatt_http_client/src/models/middleware_response.dart';
 
+/// {@template middleware}
+/// A middleware is a class that can intercept requests and responses
+/// and modify them before they are sent to the server or before they
+/// are returned to the client.
+/// {@endtemplate}
 abstract class Middleware {
-  Middleware();
+  /// {@macro middleware}
+  const Middleware();
+
+  /// The name of the middleware.
   String getName();
 }
 
 mixin OnRequestMiddleware {
+  /// Performs an action before the request is sent to the server.
   Future<MiddlewareRequest> onRequest(
     MiddlewareContext context,
     MiddlewareRequest request,
@@ -31,6 +40,7 @@ mixin OnRequestMiddleware {
 }
 
 mixin OnResponseMiddleware {
+  /// Performs an action before the response is returned to the client.
   Future<MiddlewareResponse> onResponse(
     MiddlewareContext context,
     MiddlewareResponse response,