[Suggestion] Add player self reflections

[Karpatok9089]

It would be nice to have player self reflections in first person mode on blocks, like water, reflective blocks, etc. It can be disabled if not needed for like screenshots. Image from a b1.7.3 Watershader mod

[DarianLStephens]

That mod needs to come back. Or Iris at least needs the ability to create a reflection surface that shaders can use, which actually renders the world from the correct perspective.

[EminGT]

The "Watershader mod" has access to CPU side stuff that Complementary doesn't. It's simply way too problematic to do this on completely GPU side