Action mnemonic should use crate_name instead of label.name

It isn't very clear when the crate_name doesn't match the target label.

As only the label.name is printed in the progress message, I'm seeing bunch of actions look identical:

```
Compiling Rust rlib api v0.1.0 (6 files)
Compiling Rust rlib api v0.1.0 (17 files)
```

Though they are targets with the same name in different packages.

I think it's better to use a) crate_name, idential in a workspace b) full label for clarity.