Pierre-Yves David <pierre-yves.david@fb.com> [Thu, 29 May 2014 12:25:25 -0700] rev 21632
mergetools.hgrc: add minimal configuration for editmerge
The ``editmerge`` script is shipped in contrib and opens an editor on
every conflicting file. It needs minimal configuration to inject the
config marker in the file before opening. Otherwise it behaves the
same as ``internal:local`` and bad things happen.