Implement code formatting

Author: bradleycamacho

pages/stack/interop/tutorials/convert-erc20.mdx

@@ -37,7 +37,7 @@ This implementation allows a token to be bridged between two chains. This means
 
 The following code implements a basic ERC20 contract:
 
-```
+```solidity
 // SPDX-License-Identifier: MIT
 pragma solidity ^0.8.20;
 
@@ -58,7 +58,7 @@ contract MyERC20 is ERC20, Ownable {
 
 The first step is simply to implement `IERC7802` and `IERC165`. Note that we've renamed the contract at this point:
 
-```
+```solidity
 // SPDX-License-Identifier: MIT
 pragma solidity ^0.8.20;
 
@@ -93,7 +93,7 @@ There are two functions we need to implement: `CrosschainMint` and `CrosschainBu
 Here's what our contract looks like once we've implemented the functions:
 
 
-```
+```solidity
 // SPDX-License-Identifier: MIT
 pragma solidity ^0.8.20;