ignore override expandederc20

Signed-off-by: Nick Pai <npai.nyc@gmail.com>

core/contracts/common/implementation/ExpandedERC20.sol

@@ -28,15 +28,21 @@ contract ExpandedERC20 is ExpandedIERC20, ERC20, MultiRole {
     /**
      * @dev Mints `value` tokens to `recipient`, returning true on success.
      */
-    function mint(address recipient, uint value) external onlyRoleHolder(uint(Roles.Minter)) returns (bool) {
+
+    // TODO(#969) Remove once prettier-plugin-solidity can handle the "override" keyword
+    // prettier-ignore
+    function mint(address recipient, uint value) external override onlyRoleHolder(uint(Roles.Minter)) returns (bool) {
         _mint(recipient, value);
         return true;
     }
 
     /**
      * @dev Burns `value` tokens owned by `msg.sender`.
      */
-    function burn(uint value) external onlyRoleHolder(uint(Roles.Burner)) {
+
+    // TODO(#969) Remove once prettier-plugin-solidity can handle the "override" keyword
+    // prettier-ignore
+    function burn(uint value) external override onlyRoleHolder(uint(Roles.Burner)) {
         _burn(msg.sender, value);
     }
 }