No feedback upon missing/required subcommand

[odiferousmint]

If you run pijul key, it does not print anything. I think it should print that a subcommand is missing and required. Related to this, https://pijul.org/manual/signing_patches.html is outdated. It uses subcommand keys, as in pijul keys --generate-signing, whereas it is actually key. With the latest version, that would be pijul key gen --signing.

The naming convention is kind of odd to me as well. For example:

pijul [SUBCOMMAND], AND pijul key [SUBCOMMAND]. Wouldn't it be better to use COMMAND for everything that isn't actually a subcommand? Let me know what you think.