Remove shallow renderer from website navigation

We still support it (and you can find this page in search), but we're transitioning away to community maintenance.
So we're deemphasizing it on the website.

Author: gaearon

content/docs/nav.yml

@@ -100,8 +100,6 @@
       title: SyntheticEvent
     - id: test-utils
       title: Test Utilities
-    - id: shallow-renderer
-      title: Shallow Renderer
     - id: test-renderer
       title: Test Renderer
     - id: javascript-environment-requirements
@@ -175,4 +173,4 @@
     - id: faq-versioning
       title: Versioning Policy
     - id: faq-internals
-      title: Virtual DOM and Internals
+      title: Virtual DOM and Internals