Problem/Motivation
With the introduction of #2976335: Use Zend-Feed's standalone extension managers to prevent sites breaking, it is no longer needed to maintain a list of zend services in core.services.yml since the \Drupal\Component\Bridge\ZfExtensionManagerSfContainer now passes default services unregistered to the Drupal container into the standalone extension manager.
Proposed resolution
Deprecated all feed.reader.* and feed.writer.* services in core.services.yml.
Remaining tasks
#2976335: Use Zend-Feed's standalone extension managers to prevent sites breaking
User interface changes
None
API changes
- feed.reader.* services deprecated
- feed.writer.* services deprecated
Data model changes
None