[TASK] Drop allowing Rule to be passed to RuleSet::getRules()

[JakeQZ]

... and getRulesAssoc().

Relates to #1247.

[coveralls]

coverage: 56.91% (+0.008%) from 56.902%
when pulling 383a4d2 on task/getrules-parameter
into 807a11b on main.

[JakeQZ]

Curiously, the PHPStan warning "Parameters should have "string" types as the only types passed to this method" is only generated for removeRule(), despite all three methods having Rule|string|null as the parameter type. Maybe remove in the method name has some special significance (as part of CRUD pattern) which makes it stricter.

[JakeQZ]

Curiously, the PHPStan warning "Parameters should have "string" types as the only types passed to this method" is only generated for removeRule(), despite all three methods having Rule|string|null as the parameter type. Maybe remove in the method name has some special significance (as part of CRUD pattern) which makes it stricter.

I figured out what's going on. Even after changing removeRule() to only accept Rule, PHPStan still gave the warning against the method. This turns out to be because some tests were still calling the method with string arguments. I think PHPStan could do better with its reporting, and include the source of the problem. Only when I ran the unit tests separately did it become clear, as there were then errors due to incorrect parameter types.