Don't emit `[unroll]` or `[loop]` to GLSL
Don't emit `[unroll]` or `[loop]` to GLSL

- I really ought to make these semantically understood attributes, which might make this logic easier

- Long-term if we start emitting SPIR-V directly, we should translte these, of course

csyonghe/slang,shader-slang/slang,shader-slang/slang,shader-slang/slang,csyonghe/slang,csyonghe/slang