This version allows one to either close or cancel the invariant after opening it.

These results turned out to be neither that useful nor canonical, and can easily
be derived from local updates.

This reverts commit 465dd9f4.

Thanks to @jung for proposing these names.

`sed -i 's/frag_auth_op/frac_auth_frag_op/g' $(find -name "*.v")`

fix `head_stuck`

See merge request FP/iris-coq!144

  Also, remove the inconsistency that `wp_expr_eval` succeeds on a goal
  that is not a WP.

This reverts commit 45162e5a.
We have to wait until ssreflect makes an 8.8-compatible release.

gmultiset RA

See merge request FP/iris-coq!138