diffstat: with --git, mark binary files with Bin
Normally, diffs without any text insertions or deletions are reported
as having 0 lines changed by stock diffstat. Compatibility is
preserved with stock diffstat in this case, but when using --git,
binary files are marked with Bin as a means of clarification.
git diff --stat does something similar, though it also includes the
old and new file sizes.
adding a
0 files updated, 0 files merged, 1 files removed, 0 files unresolved
% should issue warning
adding a
created new head
0 files updated, 0 files merged, 1 files removed, 0 files unresolved
% should not issue warning
0 files updated, 0 files merged, 1 files removed, 0 files unresolved
marked working directory as branch testing
% should not issue warning