[Rd] Assumption of Gaussian innovations in function stats::arima

[Peter Ruckdeschel]

Hi, if I read the help to function stats::arima carefully enough, I have not found any mentioning of the assumption that
the innovations e[t] (notation from the help file) be Gaussian. I think this assumption should be included. In
particular, the returned information on the log likelihood would be wrong otherwise.

Best regards, Peter Ruckdeschel