fix nav.adoc android section and add javascript

Author: lihaoyi

docs/modules/ROOT/nav.adoc

@@ -29,14 +29,19 @@
 // ** xref:kotlinlib/build-examples.adoc[]
 ** xref:kotlinlib/web-examples.adoc[]
 * Experimental Platform Support
-** xref:android/java.adoc[]
-** xref:android/android-linting.adoc[]
-** xref:android/kotlin.adoc[]
+** Building Android Apps
+*** xref:android/java.adoc[]
+*** xref:android/kotlin.adoc[]
+*** xref:android/android-linting.adoc[]
 ** xref:pythonlib/intro.adoc[]
 *** xref:pythonlib/module-config.adoc[]
 *** xref:pythonlib/dependencies.adoc[]
 *** xref:pythonlib/publishing.adoc[]
 *** xref:pythonlib/web-examples.adoc[]
+** xref:javascriptlib/intro.adoc[]
+*** xref:javascriptlib/dependencies.adoc[]
+*** xref:javascriptlib/module-config.adoc[]
+*** xref:javascriptlib/testing.adoc[]
 * xref:comparisons/why-mill.adoc[]
 ** xref:comparisons/maven.adoc[]
 ** xref:comparisons/gradle.adoc[]