#6 SpriteOp 50 (Plot mask scaled) is incorrect.

[Piers Wombwell]

Spotted by Codex, surprisingly. Overnight, I asked it to fix up my code after a large refactor, and it changed the comment in the header to the correct register values. I assumed its diff was wrong, but it's what the PRMs say...

OSSpriteOp_PlotMaskScaled =
( NUMBER 0x2E,
ENTRY
( R0 # 50 "Plots mask scaled",
R0 | OSSpriteOp_Flags: flags,
R1 -> OSSpriteOp_Area: area,
R2 = OSSpriteOp_Id: id,
R3 = .Int: x,
R4 = .Int: y,
R5 -> OS_Factors: factors
) ),

It should be R6 -> OS_Factors.