Change another kangax broken link

README.md

@@ -3451,7 +3451,7 @@ Other Style Guides
  this.firstName = 'Panda';
 
  // good, in environments where WeakMaps are available
- // see https://kangax.github.io/compat-table/es6/#test-WeakMap
+ // see https://compat-table.github.io/compat-table/es6/ -> Built-ins -> WeakMap
  const firstNames = new WeakMap();
  firstNames.set(this, 'Panda');
  ```