Add missing file to meson build

meson.build

@@ -98,13 +98,14 @@ src = [
 	'lib/structs/events/presence.cpp',
 	'lib/structs/events/reaction.cpp',
 	'lib/structs/events/redaction.cpp',
+	'lib/structs/events/server_acl.cpp',
 	'lib/structs/events/spaces.cpp',
 	'lib/structs/events/tag.cpp',
 	'lib/structs/events/tombstone.cpp',
 	'lib/structs/events/topic.cpp',
-	'lib/structs/events/widget.cpp',
 	'lib/structs/events/unknown.cpp',
 	'lib/structs/events/voip.cpp',
+	'lib/structs/events/widget.cpp',
 	'lib/structs/identifiers.cpp',
 	'lib/structs/pushrules.cpp',
 	'lib/structs/requests.cpp',