fix example

examples/stdin.roc

@@ -4,7 +4,7 @@ app "time"
         pf.Stdout,
         pf.Stderr,
         pf.Stdin,
-        pf.Task.{Task},
+        pf.Task.{ Task },
     ]
     provides [main] to pf
 
@@ -15,17 +15,22 @@ main =
         Stderr.line "Expected a series of number characters (0-9)"
     else
         when Str.fromUtf8 numberBytes is
-            Ok nStr -> 
+            Ok nStr ->
                 Stdout.line "Got number \(nStr)"
+
             Err _ ->
                 Stderr.line "Error, bad utf8"
 
 takeNumberBytes : Task (List U8) *
-takeNumberBytes = 
-    Task.loop [] \bytes ->
-        b <- Stdin.byte |> Task.await
-
-        if b >= '0' && b <= '9' then 
-            Task.succeed (Step (List.append bytes b))
-        else 
-            Task.succeed (Done bytes)
+takeNumberBytes =
+
+    bytesRead <- Stdin.bytes |> Task.await
+
+    numberBytes =
+        List.walk bytesRead [] \bytes, b ->
+            if b >= '0' && b <= '9' then
+                List.append bytes b
+            else
+                bytes
+
+    Task.succeed numberBytes