fix line comments with control blocks

[drecouse]

Line comments used on control blocks like this made the content inside the control block disappear:

LineComment(For([...], {
  Assign([...])
}), [comment])

[quachpas]

Hi @drecouse, thanks for the patch. Would you be able to create a test for that specific behaviour code?

[drecouse]

Sure, I have added a test with nested for and while blocks.

[quachpas]

That looks perfect! Thank you!