First Draft: Making printf @safe

[IchorDev]

On Wednesday, 17 July 2024 at 00:42:03 UTC, Walter Bright wrote:
> https://github.com/WalterBright/documents/blob/ed4f1b441e71b5ac5e23a54e7c93e68997981e9a/SafePrintf.md

`printf` always performs pointer arithmetic, and therefore 
[should not be marked 
`@safe`](https://dlang.org/spec/function.html#safe-functions):
> No pointer arithmetic (including pointer indexing & slicing).

Marking it as `@trusted` is fine, and historically other 
`core.stdc` functions that have similar behaviour have also been 
marked `@trusted`.