update style for content Supported Data Sources in readme

Author: DMGithubPublisher

README.md

@@ -116,7 +116,8 @@ Dynamsoft.BarcodeReader.productKeys = 'PRODUCT-KEYS';
 
   Postal Code: **`USPS Intelligent Mail`**, **`PostNet`**, **`Planet`**, **`Australian Post`**, **`UK Royal Mail (RM4SCC)`**.
 
-* Supported Data Sources: **`Blob`**, **`HTMLImageElement`**, **`HTMLVideoElement`**, and **`URL`**, etc.
+#### Supported Data Sources: 
+  **`Blob`**, **`HTMLImageElement`**, **`HTMLVideoElement`**, and **`URL`**, etc.
 
 #### Browser Compatibility: