Fix JSON fragment

Author: gspencergoog

docs/a2ui_protocol.md

@@ -434,26 +434,35 @@ This message provides a feedback mechanism for the server. It is sent when the c
 
     ```json
     {
-      "id": "submit_btn_text",
-      "component": {
-        "Text": {
-          "text": { "literalString": "Submit" }
-        }
-      }
-    },
-    {
-      "id": "submit_btn",
-      "component": {
-        "Button": {
-          "child": "submit_btn_text",
-          "action": {
-            "name": "submit_form",
-            "context": [
-              { "key": "userInput", "value": { "path": "form.textField" } },
-              { "key": "formId", "value": { "literalString": "f-123" } }
-            ]
+      "surfaceUpdate": {
+        "components": [
+          {
+            "id": "submit_btn_text",
+            "component": {
+              "Text": {
+                "text": { "literalString": "Submit" }
+              }
+            }
+          },
+          {
+            "id": "submit_btn",
+            "component": {
+              "Button": {
+                "child": "submit_btn_text",
+                "action": {
+                  "name": "submit_form",
+                  "context": [
+                    {
+                      "key": "userInput",
+                      "value": { "path": "form.textField" }
+                    },
+                    { "key": "formId", "value": { "literalString": "f-123" } }
+                  ]
+                }
+              }
+            }
           }
-        }
+        ]
       }
     }
     ```