Update fraxtal.mdx (added explorer details) (#778)

Co-authored-by: Milap Sheth <milap@axelar.network>

src/pages/validator/external-chains/fraxtal.mdx

@@ -176,7 +176,7 @@ If you get something like this in response to the above rpc call, your node is s
 }
 ```
 
-You can compare the block height on your node with explorer ([mainnet](https://explorer.mainnet.frax.com) or [testnet](https://explorer.testnet.frax.com)),
+You can compare the block height on your node with explorer ([mainnet](https://fraxscan.com) or [testnet](https://holesky.fraxscan.com)),
 use your RPC node only when it has caught up with the latest block height.
 
 #### Sync Status of Frax optimism Execution Node