share: allow trailing newline on .hg/sharedpath.
This is extremely handy for those occasional circumstances where you
need to edit .hg/sharedpath manually, since modern Unix text editors
make it surprisingly difficult to create a text file with no trailing
newline.
contrib: some support for named branches in zsh_completion (
issue2988)
named branches were not included for autocompletion in zsh. by adding
_hg_branches and calling it from _hg_labels, named branches are now included
when autocompleting many commands in zsh. support for completion of hg log -b
was also added. there are possibly other cases where support needs to be
explicitly added.