Better `potiontype:`

[Maroon28]

Currently, potiontype only lets you specify the potion effects, and that's it. It'd be great if we can include the level and duration too! Something like potiontype:SLOWNESS:0:600 would give slowness 1 for 30 seconds, or 600 ticks.

[Maroon28]

Already possible with potionupgraded: and potionextended:, I'm blind!