rust 1.94

Hi!

I'm planning to update lang/rust to 1.94.1 using the package in
wip/rust194 (from he@ with help from adam@ and pin@).

bulk-test-rust is fine.

This will fix a CVE in the tar crate and help with some rust packages
that already need rust 1.92 or newer.

I'm currently waiting for wip/rust194-bin to provide the same version,
and for Illumos fixes for wip/rust194, so this is a heads-up for the
commit that will follow when these are in.

Cheers,
 Thomas