anchor.diff:  --
   This CIP limits the scope of `EXISTS` to existential subqueries and removes the syntax for property existence check.
   This check is enabled by `IS NOT NULL`.
  +It changes the syntax of existence constraints to be aligned with that removal.
   --
   
   toc::[]
  
positive.code:                  | with
                   ;
  ----
  
  === Semantics
  
  
negative.code: == Caveats to this proposal
  
  * The idiomatic syntax for property existence checks is removed.
  * The syntax for creating and dropping node and relationship property existence constraints needs to be changed as well, to be aligned with the other syntax changes.
  