properly passing strings to functions? (C++ vs D)

[IGotD-]

On Tuesday, 12 January 2021 at 18:12:14 UTC, Q. Schroll wrote:
>
> Did you consider `in`? It will do that in some time and do it 
> now with -preview=in.
> If you're using `const`, in almost all cases, `in` will work, 
> too, and be better (and shorter).

Has the redesignation of "in" like in the preview been formally 
accepted as a part of language? I know that it was suggested to 
make "in" the optimized parameter passing for const which I like. 
However, if I'm going to use it I need to know if this going to 
be accepted as I don't want go around and change all the 
parameters back again if it was not accepted.