Merge branch 'jk/shortlog-group-by-trailer'
"git shortlog" has been taught to group commits by the contents of
the trailer lines, like "Reviewed-by:", "Coauthored-by:", etc.
* jk/shortlog-group-by-trailer:
shortlog: allow multiple groups to be specified
shortlog: parse trailer idents
shortlog: rename parse_stdin_ident()
shortlog: de-duplicate trailer values
shortlog: match commit trailers with --group
trailer: add interface for iterating over commit trailers
shortlog: add grouping option
shortlog: change "author" variables to "ident"
projects / git / commit
