rust: hooks: avoid fancy progress reporting by nextest

In [0.9.109], nextest added a `--show-progress=running` mode that
shows an interactive view of currently running tests. This is nice in
interactive use. However, it's very annoying when viewing logs after the
fact, such as through `nix log ...`.

`--show-progress=none` reverts to the simple interface, reporting a
single line for each test run with no control codes.

[0.9.109]: https://github.com/nextest-rs/nextest/releases/tag/cargo-nextest-0.9.109

pkgs/build-support/rust/hooks/cargo-nextest-hook.sh

@@ -12,6 +12,7 @@ cargoNextestHook() {
     local flagsArray=(
         "--target" "@rustcTargetSpec@"
         "--offline"
+        "--show-progress=none"
     )
 
     if [[ -z ${dontUseCargoParallelTests-} ]]; then