Merge pull request #12215 from xersky/patch-5

Fix markdown code format

Author: nhsz

public/content/developers/tutorials/erc20-annotated-code/index.md

@@ -794,7 +794,7 @@ Make sure to update `_totalSupply` when the total number of tokens changes.
 
  
 
-```
+```solidity
     /**
      * @dev Destroys `amount` tokens from `account`, reducing the
      * total supply.