chore: make it easier to specify other port

When port 8000 is already in use, make it easier for users of the tutorial to change it to an different port

Author: saerdnaer

docs/tutorial/basics.md

@@ -161,7 +161,7 @@ project directory and write the following code:
 
 ~~~~ typescript twoslash [Deno]
 Deno.serve(request =>
-  new Response("Hello, world", {
+  new Response({ port: 8000 }, "Hello, world", {
     headers: { "Content-Type": "text/plain" }
   })
 );