Should there be a text format for `v128.const f16x8`?

[brendandahl]

All of the other vector types have this, so I assume we'd also want it for f16x8.

e.g. v128.const f16x8 f32 f32 f32 f32 f32 f32 f32 f32

[dtig]

At the CG meeting this week, it was decided that there should be a text format for the vector type which has fp16 elements. The suggestion you have in the example seems like the reasonable thing to do.