Bring back foreach int indexes

[Liam McGillivray]

On Sunday, 24 March 2024 at 16:33:06 UTC, Walter Bright wrote:
> When size_t is 64 bits, the reason:
>
>     foreach (int i; 0 .. array.length)

I suppose I wasn't clear enough. When I say I want it to work 
without errors, I specifically meant in the following format:
```
     foreach (uint i, entry; array)
```
I suppose for the other `foreach` format it would be nice too. 
But for the latter, it would be as easy as removing a deprecation.

My position is that the latter format should be allowed and 
removed from deprecation for the foreseeable future outside of 
code marked `@safe`, but perhaps don't allow it in `@safe` code.

I don't know if it's ever considered acceptable practice for 
runtime warnings to be automatically inserted into a program, but 
perhaps for debug builds a runtime warning can be inserted 
whenever the array is longer than, or perhaps more than 3/4 the 
size allowed by the type of `i` (as in the code above).

But if it's still considered unacceptable to have the 
now-deprecated format shown above be brought back as a language 
feature, I suggest the following as a compromise:
```
     foreach (cast uint i, entry; array)
```
and also
```
     foreach (cast uint i; 0 .. array.length)
```