Merge branch 'stable-3.1'

* stable-3.1:
  Documentation: Refactor footer to match with other plugins
  Documentation: Refactor to match other plugin documentation
  Documentation: Add missing alternative for plugin in-tree testing
  Upgrade bazlets to latest stable-2.16

Change-Id: Ic6f23b31922e2c1ed83b910b81aed84d2ba7e03d