When discarding to hand size, discard triggers can't be responded to

[Cguy7777]

Tested on the most recent codebase as I write this (latest commit: 29f9858).

To reproduce:

1. Have a permanent on the battlefield with an ability that triggers on discarding cards, such as Confessor.
2. Discard to hand size during your cleanup step.

Expected result: The triggered ability goes onto the stack, and you receive priority.
Actual result: The triggered ability immediately resolves without any chance to respond. (Its controller still makes required decisions such as targets.)

Tested cards known to be affected:

• Confessor (DiscardCardPlayerTriggeredAbility)
• Feast of Sanity (DiscardCardControllerTriggeredAbility)
• Tourach, Dread Cantor (DiscardsACardOpponentTriggeredAbility)
• Rielle the Everwise (custom triggered ability, previously reported for just this card in Rielle, the Everwise Bugs #6761)