Merge "Generate reference nav to _book.yaml for devsite builds." into mnc-mr-docs am: dc55c97296 am: 16c30a64a6
am: f1929d419b

* commit 'f1929d419b5ac003d50e4a2efc18bbeadf81245b':
  Generate reference nav to _book.yaml for devsite builds.

Change-Id: Ifda2c3062588bfb8205e59dfcc3d909a62334ddc