chore(README): add a single line description about Web IDL with a link (#504)

* chore(README): add a single line description about Web IDL with a link

This replaces the previous dismissive language and thus tries being more inclusive.

Closes #502

* Update README.md

Author: saschanaz

README.md

@@ -6,10 +6,9 @@
 
 ## Purpose
 
-This is a parser for the [Web IDL](https://heycam.github.io/webidl/) language. If
-you don't know what that is, then you probably don't need it. It is meant to be used
-both in Node and in the browser (the parser likely works in other JS environments, but
-not the test suite).
+This is a parser for [Web IDL](https://heycam.github.io/webidl/), a language
+[to specify web APIs in interoperable way](https://heycam.github.io/webidl/#introduction).
+This library supports both Node.js and the browser environment.
 
 ## Installation