Make `iDestruct ... as (cpat) "..."` work on '⌜φ⌝ ∧ P` and `⌜φ⌝ ∗ P`.
The advantage is that we can directly use a Coq introduction pattern `cpat` to perform actions to the pure assertion. Before, this had to be done in several steps: iDestruct ... as "[Htmp ...]"; iDestruct "Htmp" as %cpat. That is, one had to introduce a temporary name. I expect this to be quite useful in various developments as many of e.g. our invariants are written as: ∃ x1 .. x2, ⌜ pure stuff ⌝ ∗ spacial stuff.