Make message format an enum

lib/models/content/message.dart

@@ -15,28 +15,28 @@ abstract class MessageContent extends Content with _$MessageContent {
   @FreezedUnionValue("m.text")
   factory MessageContent.text({
     required String body,
-    String? format,
+    MessageFormat? format,
     String? formattedBody,
   }) = TextMessageContent;
 
   @FreezedUnionValue("m.notice")
   factory MessageContent.notice({
     required String body,
-    String? format,
+    MessageFormat? format,
     String? formattedBody,
   }) = NoticeMessageContent;
 
   @FreezedUnionValue("m.emote")
   factory MessageContent.emote({
     required String body,
-    String? format,
+    MessageFormat? format,
     String? formattedBody,
   }) = EmoteMessageContent;
 
   @FreezedUnionValue("m.image")
   factory MessageContent.image({
     required String body,
-    String? format,
+    MessageFormat? format,
     String? formattedBody,
     // EncryptedFile? file
     String? filename,
@@ -47,7 +47,7 @@ abstract class MessageContent extends Content with _$MessageContent {
   @FreezedUnionValue("m.file")
   factory MessageContent.file({
     required String body,
-    String? format,
+    MessageFormat? format,
     String? formattedBody,
     // EncryptedFile? file
     String? filename,
@@ -58,7 +58,7 @@ abstract class MessageContent extends Content with _$MessageContent {
   @FreezedUnionValue("m.audio")
   factory MessageContent.audio({
     required String body,
-    String? format,
+    MessageFormat? format,
     String? formattedBody,
     // EncryptedFile? file
     String? filename,
@@ -69,7 +69,7 @@ abstract class MessageContent extends Content with _$MessageContent {
   @FreezedUnionValue("m.video")
   factory MessageContent.video({
     required String body,
-    String? format,
+    MessageFormat? format,
     String? formattedBody,
     // EncryptedFile? file
     String? filename,
@@ -84,3 +84,9 @@ abstract class MessageContent extends Content with _$MessageContent {
   factory MessageContent.fromJson(Map<String, Object?> json) =>
       _$MessageContentFromJson(json);
 }
+
+@JsonEnum()
+enum MessageFormat {
+  @JsonValue("org.matrix.custom.html")
+  html,
+}

lib/widgets/renderers/event.dart

@@ -231,8 +231,7 @@ class EventRenderer extends ConsumerWidget {
                                 ) => Column(
                                   crossAxisAlignment: CrossAxisAlignment.start,
                                   children: [
-                                    format == "org.matrix.custom.html" &&
-                                            !textOnly
+                                    format == MessageFormat.html && !textOnly
                                         ? Html(
                                             textStyle: textStyle,
                                             formattedBody!.replaceAllMapped(