fix: adjust the prompt to fit the non-described text (#206)

packages/midscene/src/ai-model/prompt/util.ts

@@ -8,7 +8,7 @@ const characteristic =
   'You are a versatile professional in software UI design and testing. Your outstanding contributions will impact the user experience of billions of users.';
 
 const contextFormatIntro = `
-The user will give you a screenshot and the texts on it. There may be some none-English characters (like Chinese) on it, indicating it's an non-English app.`;
+The user will give you a screenshot and some of the texts on it. There may be some none-English characters (like Chinese) on it, indicating it's an non-English app. If some text is shown on screenshot but not introduced by the JSON description, use the information you see on screenshot.`;
 
 const ONE_ELEMENT_LOCATOR_PREFIX = 'LOCATE_ONE_ELEMENT';
 const ELEMENTS_LOCATOR_PREFIX = 'LOCATE_ONE_OR_MORE_ELEMENTS';