D3984: merge: do the trivial resolution after updating sparse checkout

[yuja (Yuya Nishihara)]

yuja added a comment.


  I didn't come up with an example where d/c or c/d conflicts resolved by
  `_resolvetrivial()` had to be fixed up by `_forgetremoved()`.
  
  Queued for stable, thanks.

REPOSITORY
  rHG Mercurial

REVISION DETAIL
  https://phab.mercurial-scm.org/D3984

To: pulkit, #hg-reviewers
Cc: yuja, mercurial-devel