blake3: Convert `*const [n]u8` types to `[n]u8`

I do not see many cases of constant pointers to arrays in the stdlib.
In fact, this makes the code run a little faster, probably because Zig
automatically converts to pointers where it makes sense.
d098e212adJay Petacat committed on 2/2/2020, 7:08:10 PMparent4b86c1e
1 file changedLine totals unavailable