hook_ENTITY_TYPE_translation_delete not called

Problem/Motivation

hook_ENTITY_TYPE_translation_delete not called when an entity is deleted.

Steps to reproduce

To reproduce:

1. Write a hook_ENTITY_TYPE_delete implementation and put a \Drupal::logger(__FUNCTION__)->notice(__FUNCTION__) inside of it
2. Write a hook_ENTITY_TYPE_translation_delete implementation and put a \Drupal::logger(__FUNCTION__)->notice(__FUNCTION__) inside of it
3. Create a node in the site default language
4. Translate the node into another language
5. Delete the node in the default language

Expected result:

1. You see the notice that the node will be deleted in all the languages
2. You get a log message that shows hook_ENTITY_TYPE_delete was called
3. You get a log message that shows hook_ENTITY_TYPE_translation_delete was called

Actual result:

1. You see the notice that the node will be deleted in all the languages
2. You get a log message that shows hook_ENTITY_TYPE_delete was called
3. You DO NOT get a log message that shows hook_ENTITY_TYPE_translation_delete was called

Note: If you directly delete a given translation you DO get a log message that shows that hook_ENTITY_TYPE_translation_delete was called.

Proposed resolution

Update hook documentation

Remaining tasks

Patch
Review
Make followup, #17
commit

User interface changes

N/A

API changes

N/A

Data model changes

N/A

Release notes snippet

N/A