Support "can't infer type parameter" error for uninstantiated generic modules

[HertzDevil]

This snippet:

class Foo(T)
  def self.foo(&block : T -> )
    block
  end
end

Foo.foo { |x| } # Error: can't infer the type parameter T for the generic class Foo(T). Please provide it explicitly

produces a less specific error undefined constant T if Foo were a generic module instead. This PR changes that.

The same will also apply if T is used in foo's body:

module Foo(T)
  def self.foo
    T.bar
  end
end

Foo.foo # Error: can't infer the type parameter T for the generic module Foo(T). Please provide it explicitly

For classes this often happens with code like Array.new.

[beta-ziliani]

Awesome, thanks!