restore --help for `qbpm config`

why did I disable it?

CHANGELOG.md

···
+# next
+  - add `--help` flag to `qbpm config`
+
 # ~2.1~ 2.2
   - `config.toml` supports `application_name` for generated XDG desktop files
     - defaults to `{profile_name} (qutebrowser profile)`, you may want just `{profile_name}`

src/qbpm/main.py

···
     exit_with(exists)
 
 
[e-mail](context_settings={"help_option_names": []})
[e-mail]()
 def config() -> None:
     """Commands to create a qbpm config file.