Add or delete a warning string from the
General Form: (toggle-inhibit-warning string)
Note: This is an event! It does not print the usual event summary
but nevertheless changes the ACL2 logical world and is so recorded.
It is local to the book or encapsulate form in which it
occurs; see toggle-inhibit-warning! for a corresponding non-local event. Indeed,
The given string is added to the list of inhibited warnings if it is not
there already and is deleted from the list if it is there. Case is