!16824 更新文件相关接口

Merge pull request !16824 from 冯泽悟/OpenHarmony-3.2-Beta5

zh-cn/application-dev/reference/apis/js-apis-image.md

@@ -948,7 +948,7 @@ createImageSource(uri: string): ImageSource
 
 ```js
 let context = featureAbility.getContext();
-let path = context.getCacheDir() + "test.jpg";
+let path = context.cacheDir() + "test.jpg";
 const imageSourceApi = image.createImageSource(path);
 ```