display singular times in the past correctly

elm/PrettyDate.elm

@@ -47,7 +47,7 @@ format relativeTime =
format' prefix suffix unit n =
    let (singular, plural) = stringForm unit
    in if n == 1
       then prefix ++ singular
       then prefix ++ singular ++ suffix
       else prefix ++ toString n ++ " " ++ plural ++ suffix
toRelativeTime : Float -> RelativeTime