* lisp/gnus/*registry.el: Use slot names rather than initarg names

* lisp/gnus/*registry.el: Use slot names rather than initarg names

* lisp/gnus/registry.el (registry-lookup-breaks-before-lexbind)
(registry-search, registry-delete, registry-size, registry-insert)
(registry-reindex, registry-collect-prune-candidates, registry-lookup):
* lisp/gnus/gnus-registry.el (gnus-registry-fixup-registry)
(gnus-registry-remove-extra-data): Use slot names rather than initarg
names in `oref' and `oset'.