fix sth

Author: rebeccakak

info/api/WebTwain_IO.md

@@ -1341,7 +1341,7 @@ ConvertToBlob(
 
 **Usage notes**
 
-`getData()` returns the pure base64 string without the data URI scheme. For example, "/9j/4AAQSkZJRgABA...". If you want to use the string, you probably need to add the scheme. For example, "data:image/png; base64, /9j/4AAQSkZJRgABA...".
+`getData()` returns the blob string without the data URI scheme. For example, "/9j/4AAQSkZJRgABA...". If you want to use the string, you probably need to add the scheme. For example, "data:image/png; base64, /9j/4AAQSkZJRgABA...".
 
 **Example**