New rule: use_descriptive_names_for_type_parameters (when there's 3 or more)

[danylo-safonov-solid]

BAD:

class SomeClass<T, U, K> {
  ...
}

GOOD:

class SomeClass<$firstParam, $secondParam, $thidParam> {
  ...
}

GOOD:

class OtherClass<T> {
  ...
}

[illia-romanenko]

How we can define what is descriptive? By length? How often this case happens?