Update isolates.md: Robust Example Fix (#5725)

Fix robust example inconsistency. The constructor signature changes
order of parameters mid example which causes issues for a person
following along step by step.

---------

Co-authored-by: Parker Lougheed <parlough@gmail.com>

Author: maryamshal

examples/concurrency/lib/robust_ports_example/spawn_1.dart

@@ -30,7 +30,7 @@ class Worker {
     _commands.send(message);
   }
 
-  Worker._(this._commands, this._responses) {
+  Worker._(this._responses, this._commands) {
     // TODO: Initialize main isolate receive port listener.
   }
 

examples/concurrency/lib/robust_ports_example/spawn_2.dart

@@ -30,7 +30,7 @@ class Worker {
     final (ReceivePort receivePort, SendPort sendPort) =
         await connection.future;
 
-    return Worker._(sendPort, receivePort);
+    return Worker._(receivePort, sendPort);
   }
 // #enddocregion worker-spawn
 
@@ -39,7 +39,7 @@ class Worker {
     _commands.send(message);
   }
 
-  Worker._(this._commands, this._responses) {
+  Worker._(this._responses, this._commands) {
     // TODO: Initialize main isolate receive port listener.
   }
 

examples/concurrency/lib/robust_ports_example/start.dart

@@ -18,7 +18,7 @@ class Worker {
     throw UnimplementedError();
   }
 
-  Worker._(this._commands, this._responses) {
+  Worker._(this._responses, this._commands) {
     // TODO: Initialize main isolate receive port listener.
   }
 

src/content/language/isolates.md

@@ -560,7 +560,7 @@ class Worker {
     throw UnimplementedError();
   }
 
-  Worker._(this._commands, this._responses) {
+  Worker._(this._responses, this._commands) {
     // TODO: Initialize main isolate receive port listener.
   }
 
@@ -689,7 +689,7 @@ class Worker {
     final (ReceivePort receivePort, SendPort sendPort) =
         await connection.future;
 
-    return Worker._(sendPort, receivePort);
+    return Worker._(receivePort, sendPort);
   }
 ```