Detailed contribution stats by author is not using mailmap

[seeeebaaaa]

Description

The display of detailed contribution stats by author (git-py-stats -T) is not using the mailmap correctly, as the pretty format is using the wrong syntax.

To show auther names and emails with git log while respecting the mapped names from the .mailmap file, the pretty-format syntax should use %aN and %aE instead of %an/%ae. See documentation.

Steps to reproduce

Look at git-py-stats -T while using a mailmap.

I'll open a PR later today.