simplemerge: use same newline detection for :mergediff as for :merge[3]...
simplemerge: use same newline detection for :mergediff as for :merge[3]
The `:merge` and `:merge3` markers used the newline style detected
from the base input. The `:mergediff` style always used LF as newline
character. This patch teaches `:mergediff` to use the same detection
as the others did.
Differential Revision:
https://phab.mercurial-scm.org/D11976
