--quiet should prevent task output from going to stderr

[mcdonc]

If you use --quiet, it prevents this output from being sent to the console:

• Building shell ...
• Using Cachix: devenv
✔ Building shell in 0.2s.
• Entering shell

But task output is still shown:

Running tasks     devenv:enterShell
Succeeded         devenv:enterShell 11ms
1 Succeeded                         12.12ms

The reason it matters is that I'm trying to wrap devenv to implement a CLI and I'm passing subcommands in like "ls" e.g. devenv --quiet shell ls, which should just behave output-wise like normal ls.

I wish I could easily implement this, but I am Rust-ignorant at this point. :(