Merge branch 'update-doc-hoover' into 'develop'

Add legend for output colored images of Hoover Compare Segmentation

See merge request !800
2 jobs for nightly in 2 minutes and 44 seconds (queued for 2 seconds)
Status Name Job ID Coverage
  Precheck
passed fast-build #39802

00:02:44

 
  External
passed cdash:ubuntu-18.04-fast