Alexander Drozdov <al.drozdov@gmail.com> [Mon, 10 Feb 2014 07:13:10 +0400] rev 20606
ui: edit(): transplant: set HGREVISION environment variable for an editor
transplant command set 'transplant_source' extra for the revision.
Allow an editor to access the extra using HGREVISION environment variable.
This may be useful when an editor is actually a script which modifies a commit
message. Transplant filters is an alternative way to do it.