Add new Style/AccessorGrouping cop

[fatkodima]

Closes #3983

# EnforcedStyle: grouped (default)

# bad
class Foo
  attr_reader :bar
  attr_reader :baz
end

# good
class Foo
  attr_reader :bar, :baz
end


# EnforcedStyle: separated

# bad
class Foo
  attr_reader :bar, :baz
end

# good
class Foo
  attr_reader :bar
  attr_reader :baz
end

[fatkodima]

Updated.

[ghiculescu]

FYI, this cop is not compatible with sorbet. See this example.

This code:

class Original
  extend T::Sig

  sig { returns(String) }
  attr_reader :foo
  
  sig { returns(Integer) }
  attr_reader :bar
end

Is auto corrected to this:

class AutoCorrected
  extend T::Sig

  sig { returns(String) }
  attr_reader :foo, :bar

  sig { returns(Integer) }
end

[marcandre]

@ghiculescu I'm not super familiar with Sorbet yet, I imagine the "separated" style is fine. Is it mandatory, actually? I'm too lazy to look it up myself: if two readers are strings, can you write sig { returns(String) }; attr_reader :foo, :bar?

[ghiculescu]

Yes, that works. The problems are

1. that doesn't work if they return different types
2. we are autocorrecting to invalid syntax

To be fair, I'm not sure if it's rubocop's responsibility to deal with that. i'm just commenting so other sorbet users are aware of this.

[marcandre]

I believe it warrants at least a note in the doc: #8828

I believe the cop already considers comments, but maybe our notion of "comment" should be expanded for Sorbet.