Homomorphism properties for `bool_decide` + rename (bool_)decide_iff.
- Add homomorphism properties for bool_decide and True, False, →,
↔ - Rename
decide_iff→decide_extandbool_decide_iff→bool_decide_extbecause_iffis now used for the above property for↔. This is also more consistent with other extensionality properties.
Edited by Robbert Krebbers