Add Slab, Stair, and Trapdoor (Shape) Variants to Barriers

There are few translucent blocks in Minecraft, and very few completely transparent blocks in Minecraft. None of the transparent blocks have the shape of a slab, stair, or trapdoor. One of those transparent blocks is the barrier, and is probably the most useful. I believe that adding a slab, stair, and trapdoor shaped barrier block would be very helpful in some cases of map-making. This would allow for more flexibility with the height and width dimensions of rooms, maps, walls, etc. made out of barriers.

Without barrier slabs, there is no such thing as a 1.5/2.5 block tall room with a barrier roof, unless you're using slabs, which are limited in variant.

Having an invisible block, (a barrier slab/staircase,) that you could also walk up without being required to jump, can come in handy, (ex. invisible staircases upwards.)

The trapdoor variant of the barrier wouldn't be an actual trapdoor, but would just inhibit the shape of a trapdoor and the properties of placement. So "trapdoor" barriers could be placed on walls, ceilings, etc. and would not take up so much space as to allow the player to still walk by it. A good use for this would to be to place these barrier "trapdoors" in front of doors, making them impossible to open by players, and not easily noticeable that there is a barrier there, because currently, placing barriers in front of doors takes up a WHOLE block and is a nuisance.