Fix parsing of dangling things

[Morriar]

Comments dangling from a scope where returned reversed:

module M
  # comment 1
  # comment 2
end

was returning:

module M
  # comment 2
  # comment 1
end

Signatures left dangling at the end of a scope where ignored:

module M
  sig { void }
end

so the RBI built looked like:

module M
end