Fix links in http://bazel.io/docs/skylark/

--
MOS_MIGRATED_REVID=112766331

site/docs/skylark/index.md

diff --git a/site/docs/skylark/index.md b/site/docs/skylark/index.md
index 49164ff..92f53ad 100644
--- a/site/docs/skylark/index.md
+++ b/site/docs/skylark/index.md
@@ -11,7 +11,7 @@
 
 ## Getting started
 
-Read the [concepts](concepts.md) behind Skylark and try the
-[cookbook examples](cookbook.md). To go further, read about the
+Read the [concepts](concepts.html) behind Skylark and try the
+[cookbook examples](cookbook.html). To go further, read about the
 [standard library](lib/globals.html).