Add missing Navigation category

Add missing Navigation category

index.rst

@@ -102,6 +102,7 @@ The main documentation for the site is organized into the following sections:
    tutorials/inputs/index
    tutorials/io/index
    tutorials/math/index
+   tutorials/navigation/index
    tutorials/networking/index
    tutorials/performance/index
    tutorials/physics/index

tutorials/navigation/index.rst

@@ -1,3 +1,6 @@
+Navigation
+==========
+
 .. toctree::
    :maxdepth: 1
    :name: toc-learn-features-navigation