Fix handling of errors from pre-commit-checks

* Change `E_Type_Mixin._get_child` to use `_child_kw ("change")` for
  `Instance`: otherwise, `change` resources don't get their entries from
  `child_postconditions_map` and `child_permission_map`

* Change `_NC_Mixin_._new_child_x` to always call `_child_kw`:
  otherwise, `create` resources don't get their entries from
  `child_postconditions_map`

* Change `_Changer_._rendered_post` to handle commit error properly.

  `fv.submission_errors` is a `Once_Property`, the old implementation
  changed error-lists used by the calculcation of `submission_errors`
  after the calculcation was done which isn't at all useful.
Add `lib_dirs` to output of subcommand `info`