Provide an API / option to get shortened commit

[blueyed]

It would be nice if fugitive could use abbreviated commit hashes by default and/or allow to get it through buffer_commit.

[tpope]

You mean something like buffer.commit()[0:6]? I'm not sure I see a need to complicate the API just for that.

[tpope]

The new way to get this would be something like matchstr(FugitiveParse()[0], '^\x\{7\}'). I don't think I'll be providing a dedicated API for this. Using shortened hashes by default means more rev-parse calls when we need to get the full hash back, not an acceptable tradeoff in my book.