Move Skylark rules to build-encyclopedia.

It's probably easier for users if all available rules are listed in the
same place. It also makes the left menu cleaner.

--
MOS_MIGRATED_REVID=102647614
diff --git a/site/docs/supported-rules.md b/site/docs/supported-rules.md
deleted file mode 100644
index d763952..0000000
--- a/site/docs/supported-rules.md
+++ /dev/null
@@ -1,17 +0,0 @@
----
-layout: documentation
----
-
-# Supported Skylark Rules
-
-The Bazel team provides a set of supported build rules written using the
-[Skylark](/docs/skylark/index.html) rules framework. These rules allow you
-to build the following:
-
-*   [Closure libraries](https://github.com/bazelbuild/bazel/tree/master/tools/build_rules/closure)
-*   [Docker images](https://github.com/bazelbuild/bazel/tree/master/tools/build_defs/docker)
-*   [Groovy projects](https://github.com/bazelbuild/bazel/tree/master/tools/build_defs/groovy)
-*   [Java App Engine applications](https://github.com/bazelbuild/bazel/tree/master/tools/build_rules/appengine)
-*   [D projects](https://github.com/bazelbuild/bazel/tree/master/tools/build_defs/d)
-*   [Rust projects](https://github.com/bazelbuild/bazel/tree/master/tools/build_rules/rust)
-*   [Scala projects](https://github.com/bazelbuild/bazel/tree/master/tools/build_defs/scala) - experimental
diff --git a/src/main/java/com/google/devtools/build/docgen/templates/be-header.vm b/src/main/java/com/google/devtools/build/docgen/templates/be-header.vm
index c0bee73..97f5303 100644
--- a/src/main/java/com/google/devtools/build/docgen/templates/be-header.vm
+++ b/src/main/java/com/google/devtools/build/docgen/templates/be-header.vm
@@ -134,6 +134,31 @@
 #summaryTable($otherSummaryFamilies)
 
 </table>
+
+<h4>Rules implemented as Skylark extensions</h4>
+
+The Bazel team provides a set of supported build rules written using the
+<a href="/docs/skylark/index.html">Skylark</a> rules framework. These rules
+should be explicitly <a href="#load">load</a>ed. They allow you to build the
+following:
+
+<ul>
+<li> <a href="https://github.com/bazelbuild/bazel/tree/master/tools/build_rules/closure">
+    Closure libraries</a>
+<li> <a href="https://github.com/bazelbuild/bazel/tree/master/tools/build_defs/docker">
+    Docker images</a>
+<li> <a href="https://github.com/bazelbuild/bazel/tree/master/tools/build_defs/groovy">
+    Groovy projects</a>
+<li> <a href="https://github.com/bazelbuild/bazel/tree/master/tools/build_rules/appengine">
+    Java App Engine applications</a>
+<li> <a href="https://github.com/bazelbuild/bazel/tree/master/tools/build_defs/d">
+    D projects</a>
+<li> <a href="https://github.com/bazelbuild/bazel/tree/master/tools/build_rules/rust">
+    Rust projects</a>
+<li> <a href="https://github.com/bazelbuild/bazel/tree/master/tools/build_defs/scala">
+    Scala projects</a> - experimental
+</ul>
+
 <h2 id="common-definitions">Common definitions</h2>
 
 <p>This section defines various terms and concepts that are common to