MFC r271331:
  Change how the recommended mailing list to track is
  added to the footer of the release/doc/ pages by
  moving a hard-coded value (that is subject to human
  error to change) to release.ent where other values
  are regularly changed, and adding parsing logic to
  release.xsl.

Approved by:	re (implicit, relnotes)
Sponsored by:	The FreeBSD Foundation