synccommand-934965: Allow predictions to be an array
synccommand-934965: Allow predictions to be an array

Previously we demanded that they were a promise that resolved to an
array or a function that returned an array, but you could use just an
array.

Signed-off-by: Joe Walker <7a17872fbb32c7d760c9a16ee3076daead11efcf@mozilla.com>

joewalker/gcli,joewalker/gcli,mozilla/gcli,mozilla/gcli,mozilla/gcli