devel/ruby-zeitwerk: update to 2.6.6

2.6.2 (2022-10-31)

* Zeitwerk::Loader#load_file allows you to load an individual Ruby file.
  Check its documentation for details.

* Zeitwerk::Loader#eager_load_dir allows you to eager load a directory,
  recursively.  Check its documentation for details.

* Zeitwerk::Loader#eager_load_namespace allows you to eager a namespace,
  recursively.  Namespaces are global, this method loads only what the
  receiver manages from that namespace, if anything.  Check its
  documentation for details.

* Zeitwerk::Loader.eager_load_namespace broadcasts eager_load_namespace to
  all registered loaders.  Check its documentation for details.

* Documents shadowed files.  They always existed, but were not covered by
  the documentation.

* Other assorted documentation improvements.

2.6.3 (2022-10-31)

* v2.6.2 introduced a regression in the logic that checks whether two
  loaders want to manage the same root directories.  It has been fixed.

2.6.4 (2022-11-01)

Ruby does not have gem-level visibility, so sometimes you need things to be
public for them to be accessible internally.  But they do not belong to the
public interface of the gem.

A method that is undocumented and marked as @private in the source code is
clearly private API, regardless of its formal Ruby visibility.

This release starts a series of gradual patches in which private interface
is enforced with stricter formal visibility.

2.6.5 (2022-11-06)

* Controlled errors in a couple of situations:

  o Attempting to eager load or reload without previously invoking setup now
    raises Zeitwerk::SetupRequired.

  o The method Zeitwerk::Loader#push_dir raises Zeitwerk::Error if it gets
    an anonymous custom namespace.

* These should be backwards compatible, because they raise in circumstances
  that didn't work anyway.  The goal here is to provide a meaningful error
  upfront.

* Enforcement of private interfaces continues with another gradual patch.

2.6.6 (2022-11-08)

* The new eager_load_namespace had a bug when eager loading certain
  namespaces with collapsed directories.  This has been fixed.


(taca)