Merge pull request #667 from dynamsoft-docs/preview

Preview

Author: lunaaaw

info/api/WebTwain_Acquire.md

@@ -769,7 +769,7 @@ Bring up the Source Selection User Interface (UI) for the user to choose a data
 SelectSource(
     successCallBack?: () => void,
     failureCallBack?: (errorCode: number, errorString: string) => void
-): boolean | void;
+): boolean | string;
 ```
 
 **Parameters**