add Text Templating to the navigation menu.

docs/en/docs-nav.json

@@ -179,6 +179,10 @@
           "text": "Object to object mapping",
           "path": "Object-To-Object-Mapping.md"
         },
+        {
+          "text": "Text Templating",
+          "path": "Text-Templating.md"
+        },
         {
           "text": "Object Serialization"
         },