Missed TidRangePath in the print_path switch

Hi,

The TidRangePath node was introduced three years ago. However, path 
printing machinery still does not support it. It isn't enjoyable to add 
this string of code each time. I suggest adding it now.
Also, I propose not printing "???path" in the default case but throwing 
a warning - see the patch in the attachment. It can help to avoid such 
slip-ups next time.
It generally makes sense to generate such long switches automatically, 
likewise nodeToString.

-- 
regards,
Andrey Lepikhov
Postgres Professional