`git describe --dirty` doesn't consider untracked files to be dirty

Hi,

There seems to be a discrepancy between how `git describe --dirty` is documented and how it actually behaves. The documentation describes the --dirty flag like this:

but certain kinds of "local modification", namely untracked files, don't cause "-dirty" to be included.

Please could this be fixed, either in the documentation or in git describe?

thanks, Ash she/they