There will never be more starting head revs than their are heads.

If there's <3 heads, there'll only be as many head revs as heads
Late join heads must now be slain to win the round for the head revs

If there are less than 3 head revs and another head joins, a new headrev will be created from from the existing revolutionaries. If there are no revolutionaries that aren't already head revs, the next conversion will be raised to head revolutionary status quickly after conversion.
Merge branch 'master' of https://github.com/tgstation/-tg-station into revheadscaling
Adds the Changelog (man I hope I did this right)
Merge pull request #4846 from Incoming5643/revheadscaling

Changes to Revolution Mode