design: Move to core subdirectory

These are generally useful pages for all users of Dovecot (not just
developers).

But this is a necessity for Pro as there are links to some of these pages that
otherwise break builds (e.g. to events page)

data/updates.js

@@ -23,6 +23,7 @@ export const updates = {
 	auth_server_common_secured: '2.4.0',
 	dcrypt_same_cipher_algo_added: '2.4.0',
 	dict_idle_timeout_added: '2.4.0',
+	dict_protocol_v4: '2.4.0',
 	dict_slow_warn_added: '2.4.0',
 	doveadm_ex_expired_code: '2.4.0',
 	doveadm_mailbox_commands_user: '2.4.0',

docs/developers/design/dict_protocol.md → docs/core/design/dict_protocol.md

@@ -11,8 +11,8 @@ dovecotlinks:
 This document describes Dovecot Dict protocol v3.2 which is supported in
 Dovecot v2.3.17+.
 
-Dovecot Core v2.4.0 changed the version to v4, but it's otherwise compatible
-with v3.2
+[[changed,dict_protocol_v4]] Dict protocol version was updated to v4, but
+it's otherwise compatible with v3.2.
 :::
 
 Dovecot's dict protocol is a line based protocol between the dict client and