Fixes from review

Author: domenic

README.md

@@ -126,9 +126,9 @@ const multiUserSession = await ai.assistant.create({
 });
 
 const result = await multiUserSession.prompt([
-  { "role": "user", content: "Marketing: We need more budget for advertising campaigns." },
-  { "role": "user", content: "Finance: We need to cut costs and advertising is on the list." },
-  { "role": "assistant", "content": "Let's explore a compromise that satisfies both departments." }
+  { role: "user", content: "Marketing: We need more budget for advertising campaigns." },
+  { role: "user", content: "Finance: We need to cut costs and advertising is on the list." },
+  { role: "assistant", content: "Let's explore a compromise that satisfies both departments." }
 ]);
 
 // `result` will contain a compromise proposal from the assistant.
@@ -429,13 +429,13 @@ dictionary AIAssistantCreateOptions {
 };
 
 dictionary AIAssistantInitialPrompt {
-  AIAssistantInitialPromptRole role;
-  DOMString content;
+  required AIAssistantInitialPromptRole role;
+  required DOMString content;
 };
 
 dictionary AIAssistantPrompt {
-  AIAssistantPromptRole role;
-  DOMString content;
+  required AIAssistantPromptRole role;
+  required DOMString content;
 };
 
 dictionary AIAssistantPromptOptions {