Browserlist part 2 (#2644)

* adding details for browserlist

* ESR

Author: roblarsen

README.md

@@ -83,7 +83,10 @@ Choose one of the following options:
 * Extensive documentation.
 
 ## Browser support
-You can find our range of supported browsers in our [package.json](https://github.com/h5bp/html5-boilerplate/blob/main/package.json#L56-L62)
+HTML5-Boilerplate supports the latest, stable releases of all major browsers. 
+
+You can find our range of supported browsers in our [package.json](https://github.com/h5bp/html5-boilerplate/blob/main/package.json#L56-L62) At present we extend the [browserlist default](https://github.com/browserslist/browserslist#full-list) with the addition of IE 11 and [FireFox ESR.](https://www.mozilla.org/en-US/firefox/enterprise/)
+
 ```json
   "browserslist": [
     "> 0.5%",
@@ -93,6 +96,7 @@ You can find our range of supported browsers in our [package.json](https://githu
     "IE 11"
   ],
 ```
+
 ## Documentation
 
 Take a look at the [documentation table of contents](dist/doc/TOC.md). This