Re: -v, --verbosity=LEVEL use the given verbosity LEVEL

[jgart]

Hi Maxim,

But it's not below in the --help of `guix build` command.

It just says

> use the given verbosity LEVEL

```
[jgart@fedora_user ~]$ guix build --help
...
  -d, --derivations      return the derivation paths of the given packages
      --check            rebuild items to check for non-determinism issues
      --repair           repair the specified items
  -r, --root=FILE        make FILE a symlink to the result, and register it
                         as a garbage collector root
  -v, --verbosity=LEVEL  use the given verbosity LEVEL
  -q, --quiet            do not show the build log
...
```

But what if the user doesn't know what the verbosity LEVELs are?

And what if the user also doesn't know that they are documented in the info 
manual?