Add titles to Bazel documentation pages.

Fixes #790

--
MOS_MIGRATED_REVID=112563137
diff --git a/site/docs/getting-started.md b/site/docs/getting-started.md
index 510445b..613793c 100644
--- a/site/docs/getting-started.md
+++ b/site/docs/getting-started.md
@@ -1,5 +1,6 @@
 ---
 layout: documentation
+title: Getting Started
 ---
 
 # Getting Started with Bazel