wgsl: add unary plus?

[dneto0]

The operator precedence and associativity consensus is documented at #1146 (comment)

That has a unary plus, but the WGSL spec does not have unary plus. PR #2267 recently updated the grammar to closer match the consensus, but not in this respect.

It seems fine to me, and is symmetric with unary minus.

[litherum]

We generally don't feel that it's worth bothering with. The costs outweigh the benefits.

[kdashg]

WGSL meeting minutes 2021-11-16

• MM: Not valuable.
• Let’s close.

[dneto0]

Agreed not to add this.