change semantics of `@memcpy` and `@memset`

Now they use slices or array pointers with any element type instead of
requiring byte pointers.

This is a breaking enhancement to the language.

The safety check for overlapping pointers will be implemented in a
future commit.

closes #14040
a5c910adb6Andrew Kelley committed on 4/25/2023, 6:23:40 PMparent8d88dcd
33 files changedLine totals unavailable