[DECOHack] Warnings on Initial Frames with Action Pointers

[MTrop]

Doom has a quirk where if an actor state is set instead of advanced to normally via Thinker update, the action pointer on that target state, if any, does not get called.

This sort of thing trips up even veteran modders from time to time. Maybe a warning would be good for detecting spawn frames with an action? We might have to ignore A_Look, as it is not a big deal to skip, and detecting it would result in lots of false positives.