D644: rebase: remove complex unhiding code

[durham (Durham Goode)]

durham added a comment.


  I'd love to get rid of hidden filtering everywhere.  Just limit knowledge of "hidden" to getting the list of visible heads, and algorithms that need to traverse children.

REPOSITORY
  rHG Mercurial

REVISION DETAIL
  https://phab.mercurial-scm.org/D644

To: quark, #hg-reviewers
Cc: durham, mercurial-devel