Feature Request - flag to turn on spawnable spaces under water

[campbebj]

Im working on spawn proofing the ocean under my base and i generally rely on grid and carpetmod for determining spawnable spaces. but when it comes to underwater spawns for drowned everything sorta falls out.
It would be really great if i could at least get an option to have underwater still show light level markers, then i could at least make sure my spacing for my lights is going to cover everything.