#2883 update navigation, add documentation

Author: rjzupkoii

_data/navigation.yml

@@ -3,6 +3,9 @@
 # Changing the order here will adjust the order and you can also add additional
 # links. Removing a link prevents it from showing in the header, but does not
 # prevent it from being included in the site.
+#
+# NOTE that only one of the CV options should be selected, the first is for the
+#      Markdown formatted page while the second is generated using JSON.
 
 main:
   - title: "Publications"
@@ -23,8 +26,8 @@ main:
   - title: "CV"
     url: /cv/
 
-  - title: "JSON CV"
-    url: /cv-json/
+  # - title: "CV"
+  #   url: /cv-json/
 
   - title: "Guide"
     url: /markdown/

_pages/markdown.md

@@ -38,6 +38,8 @@ redirect_from:
 * While GitHub Pages prevents server side code from running, client-side scripts are supported.
   * This means that Google Analytics is supported, and [the wiki](https://github.com/academicpages/academicpages.github.io/wiki/Adding-Google-Analytics) should contain the most up-to-date information on getting it working.
 
+* Your CV can be written using either Markdown ([preview](https://academicpages.github.io/cv/)) or generated via JSON ([preview](https://academicpages.github.io/cv-json/)) and the layouts are slightly different. You can update the path to the one being used in `_data/navigation.yml` with the JSON formatted CV being hidden by default.
+
 ## Resources
  * [Liquid syntax guide](https://shopify.github.io/liquid/tags/control-flow/)
  * [MathJax Documentation](https://docs.mathjax.org/en/latest/)