[feature request] breakdown by language

[travischambers]

These summaries are so fun! However, it could be helpful to break down stats by language. This is especially apparent in monorepos.

e.g. if I've contributed 200 lines of python code, but deleted 200,000k lines of json, the current git-stats summary doesn't really tell the whole story.

[lukehsiao]

Hmm, I hear you, but I have no idea what this might look like. I.e., I don't have a good idea of what the output would look like.

In addition, git shortlog doesn't actually give any of that info directly, so likely would be relatively high effort to implement.