patch: add config knob for displaying the index header This config knob can take an integer between 0 and 40 or a keyword ('none', 'short', 'full') to control the length of hash to output. It will display diffs with the git index header as such, diff --git a/mercurial/mdiff.py b/mercurial/mdiff.py index 112edf7..d6b52c5 100644 We'll put this in the experimental section for now.