third draft: add bitfields to D

[Dave P.]

On Sunday, 5 May 2024 at 23:08:29 UTC, Walter Bright wrote:
> https://github.com/WalterBright/documents/blob/2ec9c5966dccc423a2c4c736a6783d77c255403a/bitfields.md
>
> Adds introspection capabilities.
>
> https://github.com/dlang/dmd/pull/16444

Wouldn’t a more D-like syntax be to have the number of bits 
following the type instead of following the variable name? This 
would be more consistent with how D arrays are different than C 
arrays.

Example:

```
struct Foo {
     uint:4 x;
     uint:5 y;
}
```