Draft picks "ED" category not in use

[crunkilton]

In the datasets readme for draft picks, the category column is described with the following:

For defense, this can be DB, DL, ED (edge), or LB. Note that ED is only used from 2019 forward.

However, it doesn't look like the "ED" designation appears anywhere in the CSV.

If this is expected that's fine! But probably worth a PR to update the docs if so.