fix: correctly print help when only command found and passed with help

[WillieRuemmele]

@W-13753346@
forcedotcom/cli#2301

[mshanemc]

QA:

✅ sf project create -h
✅ sf project create --help (create is an alias for generate)
✅ sf project generate -h
[error because it's not a real command] sf project generate create -h

💡 it'd be cool if this also ran the "plugin-not-found/did-you-mean" hook. I got it to run, but it was also throwing a TypeError.

 ›   Warning: project generate create is not a sf command.
Did you mean project generate manifest? [y/n]:     TypeError: this.config.runHook(...) is not a function