[Proposal]: Unsigned `sizeof`

[jnm2]

Unsigned sizeof

• Specification: https://github.com/dotnet/csharplang/pull/9634/files [TEMPORARY URL]
• Discussion: Please make sizeof(T) compatible with uint/nuint #5399

Summary

This proposal enables sizeof expressions without a constant value to implicitly convert to unsigned integer types the same size as uint or larger:

uint size = sizeof(SomeStruct);