Creep.rangedHeal does not work on Power Creeps

[Orlet]

> Game.creeps.Apothecary16253996.rangedHeal(Game.powerCreeps.Aricia)
< 0

Apothecary16253996 is a small [HEAL, MOVE] creep.Aricia is, well, a Power Creep. They were in range of each other (at 3sq) but no healing beam, no hitpoint bonus. Return code was OK. Normal .heal() worked, though.

replay: screeps.com/s/Rag6GS

I made the healer say *pew!* whenever I told it to heal the power creep.

[o4kapuk]

@orlet Thanks, we'll take a look