Fix outdated convert_saop_to_hashed_saop comment
In
29f45e299, we added support for optimizing the execution of NOT
IN(values) by using a hash table instead of a linear search over the
array. That commit neglected to update the header comment for
convert_saop_to_hashed_saop() to mention this fact. Here we fix that.
Author: James Coleman
Discussion: https://postgr.es/m/CAAaqYe99NUpAPcxgchGstgM23fmiGjqQPot8627YgkBgNt=BfA@mail.gmail.com
Backpatch-through: 15, where
29f45e299 was added.