Update polymer tutorial; make directory paths match new sample structure

src/site/docs/tutorials/streams/index.markdown

Index: src/site/docs/tutorials/streams/index.markdown
diff --git a/src/site/docs/tutorials/streams/index.markdown b/src/site/docs/tutorials/streams/index.markdown
index 21f9c63e90658d6cd96e3b1fbae1159f29d87a09..5ab9550e33a2183fafec50bd91fbbb6381eca2c3 100644
--- a/src/site/docs/tutorials/streams/index.markdown
+++ b/src/site/docs/tutorials/streams/index.markdown
@@ -28,8 +28,8 @@ has-permalinks: true
 {% capture sample_links %}
 
 
-<p markdown="1"> This tutorial features these examples
-in the `bin` directory:</p>
+<p markdown="1"> This tutorial features these examples,
+which live under the **streams** directory:</p>
 
 * feet_wet_streams.dart
 * html_streams.dart