* etc/committer.scm.in (hunk-types): New variable.
(<hunk>): Rename hunk-definition? getter to 'hunk-type'.
(diff-info): Mute a git warning by separating file names from arguments with
'--'. Rename the 'definitions?' variable to 'type'.
Use the 'addition type when a new package addition is detected, 'removal when
removed else #f.
(add-commit-message): Re-indent.
(remove-commit-message): New procedure.
(main)[definitions]: Make commit message conditional depending on whether it
is an addition or removal.
[changes]: Adjust indentation.
5e6efdfeec