CLN: remove LegacyFoo from io.pytables
> i would add a notet o what’s new as well

ok.  saying what?  its not actually clear to me what these unused classed _did_ that we are removing support for just say that we removed legacy HDf5 support which was for pandas files written in version xxx (have to see if can figure when)

it’s  likely pretty old though like 0.11 or something added a note, couldn't be too specific; looking through the blame i didnt see anything except "legacy", and the last relevant change was from 2013 with no attached PR thanks!