WGSL doesn't support matrices with elements of integer type

[aleino-nv]

It seems WGSL doesn't support matrices with entries of integer type, though it does allow vector types with integer entries.

I think it makes sense to also support integer matrices, especially since integer vectors are already supported. (For example, it could help save size or precision if you have a matrix where most non-zero elements would have the same floating point exponent.)

[dj2]

Looking at the MSL spec, I don't see integer type matrices as supported, only float and half matrices. So, this would have to be polyfilled on MSL if it was done.