Merge branch 'jk/mailmap-from-blob'

Allow us to read, and default to read, mailmap files from the tip of the history in bare repositories. This will help running tools like shortlog in server settings. * jk/mailmap-from-blob: mailmap: default mailmap.blob in bare repositories mailmap: fix some documentation loose-ends for mailmap.blob mailmap: clean up read_mailmap error handling mailmap: support reading mailmap from blobs mailmap: refactor mailmap parsing for non-file sources