docs: Fix code indentation on Caching and Serialization pages

docs/06-concepts/03-serialization.md

@@ -6,21 +6,21 @@ For most purposes, you will want to use Serverpod's native serialization. Howeve
 
     ```dart
     Map<String, dynamic> toJson() {
-    return {
+      return {
         name: 'John Doe',
-    };
+      };
     }
     ```
 
 2. There must be a constructor or factory called `fromJson()`, which takes a JSON serialization as parameters.
 
     ```dart
     factory ClassName.fromJson(
-    Map<String, dynamic> json,
+      Map<String, dynamic> json,
     ) {
-    return ClassName(
+      return ClassName(
         name: json['name'] as String,
-    );
+      );
     }
     ```
 

docs/06-concepts/08-caching.md

@@ -87,7 +87,7 @@ Future<UserData> getUserData(Session session, int userId) async {
       () async => UserData.db.findById(session, userId),
       lifetime: Duration(minutes: 5),
     ),
-    );
+  );
 
   // Return the user data to the client
   return userData;