Clarify what `more` means

[simPod]

Readme says

Traditionally, command buses can obscure static analysis. The Tactician PHPStan plugin helps bring stronger type checking by finding missing handler classes, validating handler return types and more.

I wanted to test the extension so I created checklist what to test:

• [x] finding missing handler classes -> Checks missing handler clasess well on my project
• [x] validating handler return types -> Can confirm return types are infered
• [x] and more -> I could not test that 😢

[rosstuck]

Haha, fair enough.

Other things that get checked:

• missing handler methods (not just classes)
• mismatch in parameters (not enough, too many, wrong typehints, etc)
• all the goodness that comes from "lifting" the handler's return type to the command bus's return type, like checking for unnecessary null checks in the controller or finding type mismatch in the call site.

[rosstuck]

(will add to the docs)