Indent tuples when printing

[julianhyde]

Tuples should be indented when printing, just as lists are today.

For example, a long tuple on a short line today appears as

val y = ([1,2,3],[4,5],[6],[]);
> val it =
>   ([1,2,3],[4,5],[6],
>   [])
>   : int list * int list * int list * 'a list

but should appear as

val y = ([1,2,3],[4,5],[6],[]);
> val it =
>   ([1,2,3],[4,5],[6],
>    [])
>   : int list * int list * int list * 'a list

Note that []) should be indented 3 where ([1,2,3],[4,5],[6], is only indented 2.