warning on push should mention heads, not branches
This makes the concept easier to relate to similar messages given on pull,
and allows for a distinction between heads and (named) branches.
0 files updated, 0 files merged, 1 files removed, 0 files unresolved
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
(branch merge, don't forget to commit)