Merge branch 'stable-2.16' into stable-3.0

* stable-2.16:
  Set version to 2.15.19-SNAPSHOT
  Set version to 2.15.18
  ReviewerUtil: Keep only AccountLoader.Factory
  Update highlight.js
  Highlight VHDL
  ListMembers: Keep only AccountLoader.Factory in REST handler

Change-Id: I3d38dfe5ea06abaee05b2d6599f9321868821988

polygerrit-ui/app/elements/diff/gr-syntax-layer/gr-syntax-layer.js

@@ -89,6 +89,7 @@
     'text/x-twig': 'twig',
     'text/x-vb': 'vb',
     'text/x-verilog': 'v',
+    'text/x-vhdl': 'vhdl',
     'text/x-yaml': 'yaml',
     'text/vbscript': 'vbscript',
   };