This way, we get more definitional equalities.

To be consistent with Iris, see Iris commit 9ee62b3a.

It is sometimes not desirable to do so.

For example, instead of:

  Notation "( X ⊆ )"

We now use:

  Notation "( X ⊆)"

We were already doing this for = and ≡.

This solves some conflicts with the notations of MetaCoq.

To make it consistent with Forall_impl and map_Forall_impl. Also, put
the premises in the same order as those lemmas.

Some were already maximally implicit, some were not. Now it is consistent.

It no longer requires the functions on both sides of the relation
to be syntactically the same.

This fixes issue #65.

This approach is originally by Robbert

Fix fixes issue #63.