registerAfterDocument(e, t = this) {
    this.entriesAfter.push(this.wrapPreparationException(e, "An error occurred during tear-down of the validation", t));
  }
Register logic which will be executed once after validating all the nodes of an AST/Langium document.
This helps to finally evaluate information which are collected during the checks on the AstNodes.

As an example, for validating unique fully-qualified names of nodes in the AST,
here the map with all the collected nodes and their names is checked
and validation hints are created for all nodes with the same name.

Note that this approach makes validations stateful, which is relevant e.g. when cancelling the validation.
Therefore it is recommended to clear stored information
_before_ validating an AST to validate each AST unaffected from other ASTs
AND _after_ validating the AST to free memory by information which are no longer used.

@param checkBefore a set-up function which will be called once before actually validating an AST
@param thisObj Optional object to be used as `this` when calling the validation check functions.