Remove dc_accounts_event_emitter_t

Use dc_event_emitter_t instead.

CHANGELOG.md

@@ -3,6 +3,13 @@
 ## Unreleased
 
 ### API-Changes
+- breaking change: replace `dc_accounts_event_emitter_t` with `dc_event_emitter_t` #3422
+
+  Type `dc_accounts_event_emitter_t` is removed.
+  `dc_accounts_get_event_emitter()` returns `dc_event_emitter_t` now, so
+  `dc_get_next_event()` should be used instead of `dc_accounts_get_next_event`
+  and `dc_event_emitter_unref()` should be used instead of
+  `dc_accounts_event_emitter_unref`.
 - add `dc_contact_was_seen_recently()` #3560
 
 ### Changes