Merge remote-tracking branch 'upstream/master' into pipeline-hooks

* upstream/master: (1174 commits)
  Added CHANGELOG
  Added unfold test to parallel and added 'diff discussion' context
  Fix Spinach branches spec
  Better first match on this MR also
  Change merge_error column from string to text type
  Fix typo in gitlab_flow.md
  entities: make Environment inherit EnvironmentBasic
  Updated to optimized specs from !5864
  Added 'with an unfolded line should not allow commenting' scenario (line 125)
  Added addtional 'renderable' validator to check 'data-note-type' attr exists
  Allow passing an index to selectRowAtIndex
  Fixed enter key in search input not working
  Fix file links on project page Files view
  Fix incorrect "stopped impersonation" log message
  8.11 is released, long live 8.12
  Also check if Akismet is enabled, before showing the `Submit as spam` button.
  fix location of markdown help location
  Fix for update 8.10-to-8.11.md doc.
  Appease the linter.
  Add Ruby 2.3 upgrade notes.
  ...