refactor(tvix/nix-compat/wire): express magics as u64 r/7875

This allows using read_u64, write_u64, which is a bit easier to juggle
with.

Also, update names to align with the nix codebase, which makes it easier
to spot both the constant name as well as the value.
Leave the ASCII interpretation as a comment afterwards.

Change-Id: I0b9ab187acd22807e2785b0722aa4300dab37c51
Reviewed-on: https://cl.tvl.fyi/c/depot/+/11378
Tested-by: BuildkiteCI
Reviewed-by: picnoir picnoir <picnoir@alternativebit.fr>
Autosubmit: flokli <flokli@flokli.de>

0 files changed, 0 insertions, 0 deletions