[readme] Updates ESLint rule in section 12.3 (exponentiation-operator)

The change itself has already been made in f3d3a07
(tracked in/acording to #2421 (comment)).


#2421
Remove Math.pow from `no-restricted-properties` and use `prefer-exponentiation-operator` instead.

Author: SpraxDev

README.md

@@ -1621,7 +1621,7 @@ Other Style Guides
     ```
 
   <a name="es2016-properties--exponentiation-operator"></a>
-  - [12.3](#es2016-properties--exponentiation-operator) Use exponentiation operator `**` when calculating exponentiations. eslint: [`no-restricted-properties`](https://eslint.org/docs/rules/no-restricted-properties).
+  - [12.3](#es2016-properties--exponentiation-operator) Use exponentiation operator `**` when calculating exponentiations. eslint: [`prefer-exponentiation-operator`](https://eslint.org/docs/rules/prefer-exponentiation-operator).
 
     ```javascript
     // bad