Removing unrequired `_burn()` override (#1373)

* signing prefix added

* Minor improvement

* Tests changed

* Successfully tested

* Minor improvements

* Minor improvements

* Revert "Dangling commas are now required. (#1359)"

This reverts commit a6889776f4.

* updates

* fixes #1371

* Removed extra whitespace

(cherry picked from commit f3888bb0b0)

contracts/token/ERC20/ERC20Burnable.sol

@@ -25,12 +25,4 @@ contract ERC20Burnable is ERC20 {
   function burnFrom(address from, uint256 value) public {
     _burnFrom(from, value);
   }
-
-  /**
-   * @dev Overrides ERC20._burn in order for burn and burnFrom to emit
-   * an additional Burn event.
-   */
-  function _burn(address who, uint256 value) internal {
-    super._burn(who, value);
-  }
 }