Change comma to decimal point in comment (#2742)

contracts/token/ERC20/ERC20.sol

@@ -72,7 +72,7 @@ contract ERC20 is Context, IERC20, IERC20Metadata {
     /**
      * @dev Returns the number of decimals used to get its user representation.
      * For example, if `decimals` equals `2`, a balance of `505` tokens should
-     * be displayed to a user as `5,05` (`505 / 10 ** 2`).
+     * be displayed to a user as `5.05` (`505 / 10 ** 2`).
      *
      * Tokens usually opt for a value of 18, imitating the relationship between
      * Ether and Wei. This is the value {ERC20} uses, unless this function is