Consistency with fast_transfer on miscellanous entities

[PFQNiet]

Suppose you have a Combinator entity that can "receive" or "output" items based on signals. For example, you "insert" an iron plate and it gets stored as a signal in the combinator. You can then "retrieve" the item.

I have something vaguely like this and it works okay. I wanted to make it more player-friendly by having it support fast transfer, only to discover:

- Ctrl+Click on an entity with an item in hand: on_player_fast_transferred triggers (even though constant-combinator is not an entity that would accept items normally)
- Ctrl+Click on an entity with an empty cursor: on_player_fast_transferred does not trigger, making it impossible to "withdraw" items.

So basically I can make my idea work but only for depositing items. I would like it if the event would trigger the other way too (ie. Ctrl+Click with empty cursor) so that I can have withdrawals work.

In the meantime, I can hook the input to detect Ctrl+Click directly on an entity, but I'd still be missing Ctrl+Click+Drag to withdraw items from multiple entities.