Missed inf in docs

[Alexey T.]

• missed inf about transition: it can begin also with
  a) ESTABLISHING
  b) I./E.
  (i dont see these)

[Danny Althoff]

https://github.com/nyousefi/Fountain/search?utf8=%E2%9C%93&q=ESTABLISHING&type=

I see this being part of the fountain-files, but not being present in the implementation, nor any documentation.