Updated Readme

Author: Kartikeya99

README.md

@@ -71,6 +71,7 @@ It is exactly same as `seeVisualDiff` function, only an additional `selector` CS
 
 Third one is the `screenshotElement` which basically takes screenshot of the element. Selector for the element must be provided.
 It saves the image in the output directory as mentioned in the config folder.
+This method only works with puppeteer.
 ```
 I.screenshotElement("selectorForElement", "nameForImage");
 ```

index.js

@@ -72,7 +72,7 @@ class ResembleHelper extends Helper {
    * Take screenshot of individual element.
    * @param selector selector of the element to be screenshotted 
    * @param name name of the image
-   * @returns {Promise<void} 
+   * @returns {Promise<void>} 
    */
   async screenshotElement(selector, name) {
     const helper = this._getHelper();
@@ -236,5 +236,4 @@ class ResembleHelper extends Helper {
     throw new Error('No matching helper found. Supported helpers: WebDriver/Appium/Puppeteer');
   }
 }
-
 module.exports = ResembleHelper;