List command using `--format=json` should print the location of the generated json file.

[celinval]

Requested feature: Print the path to the generated json file after running kani list --format=json unless --quiet is provided.
Use case: Improve the user experience when requesting a json file.
Link to relevant documentation (Rust reference, Nomicon, RFC):

Currently, the command will print the regular cargo build logs, and quietly exit after that. I was expecting Kani to either print the json to the standard output or print the location of the file.