Merge branch 'stable-3.1'

* stable-3.1:
  Set bazlets to latest stable-3.1
  Documentation: Remove bazel issue
  Documentation: Refactor to match other plugin documentation
  Documentation: Add missing plugin standalone and in-tree testing
  Upgrade bazlets to latest stable-2.16

Change-Id: I7de2a9247c84d3044e104aa2ad6f83cfacd99dca