api [nfc]: Rename Message.matchTopic, from matchSubject

Much like the `topic` field in the previous commit.

Author: gnprice

lib/api/model/events.dart

@@ -584,8 +584,8 @@ class MessageEvent extends Event {
   //
   // The other difference in the server API between message objects in these
   // events and in the get-messages results is that `matchContent` and
-  // `matchSubject` are absent here.  Already [Message.matchContent] and
-  // [Message.matchSubject] are optional, so no action is needed on that.
+  // `matchTopic` are absent here.  Already [Message.matchContent] and
+  // [Message.matchTopic] are optional, so no action is needed on that.
   final Message message;
 
   MessageEvent({required super.id, required this.message});

lib/api/model/model.dart

@@ -657,7 +657,8 @@ sealed class Message {
   @JsonKey(fromJson: _flagsFromJson)
   List<MessageFlag> flags; // Unrecognized flags won't roundtrip through {to,from}Json.
   final String? matchContent;
-  final String? matchSubject;
+  @JsonKey(name: 'match_subject')
+  final String? matchTopic;
 
   static Reactions? _reactionsFromJson(dynamic json) {
     final list = (json as List<dynamic>);
@@ -690,7 +691,7 @@ sealed class Message {
     required this.timestamp,
     required this.flags,
     required this.matchContent,
-    required this.matchSubject,
+    required this.matchTopic,
   });
 
   factory Message.fromJson(Map<String, dynamic> json) {
@@ -755,7 +756,7 @@ class StreamMessage extends Message {
     required super.timestamp,
     required super.flags,
     required super.matchContent,
-    required super.matchSubject,
+    required super.matchTopic,
     required this.displayRecipient,
     required this.streamId,
   });
@@ -857,7 +858,7 @@ class DmMessage extends Message {
     required super.timestamp,
     required super.flags,
     required super.matchContent,
-    required super.matchSubject,
+    required super.matchTopic,
     required this.displayRecipient,
   });
 

lib/api/model/model.g.dart

@@ -55,7 +55,7 @@ extension MessageChecks on Subject<Message> {
   Subject<String> get type => has((e) => e.type, 'type');
   Subject<List<MessageFlag>> get flags => has((e) => e.flags, 'flags');
   Subject<String?> get matchContent => has((e) => e.matchContent, 'matchContent');
-  Subject<String?> get matchSubject => has((e) => e.matchSubject, 'matchSubject');
+  Subject<String?> get matchTopic => has((e) => e.matchTopic, 'matchTopic');
 }
 
 extension ReactionsChecks on Subject<Reactions> {

test/api/model/model_checks.dart

@@ -561,6 +561,13 @@ void main() {
       )).topic.equals('hello');
     });
 
+    test('match_subject -> matchTopic', () {
+      check(baseStreamJson()).not((it) => it.containsKey('match_topic'));
+      check(Message.fromJson(baseStreamJson()
+        ..['match_subject'] = 'yo'
+      )).matchTopic.equals('yo');
+    });
+
     test('no crash on unrecognized flag', () {
       final m1 = Message.fromJson(
         (deepToJson(eg.streamMessage()) as Map<String, dynamic>)