Transition to @safe by default

[Walter Bright]

On 7/30/2024 9:24 AM, Dukc wrote:
> ```D
> // unattributed
> extern(c) void free(void*);
> 
> // inferred as @safe!
> auto foo() => free(new int);
> ```

That's correct.

What we could do is require functions with no bodies to have an attribute.