docs: md-to-mdx-misc

arbitrum-docs/build-decentralized-apps/01-quickstart-solidity-hardhat.mdx

@@ -520,7 +520,7 @@ If you have any questions or feedback, reach out to us on [Discord](https://disc
 [^3]: There are multiple types of Ethereum nodes. The ones that earn ETH for processing and validating transactions are called _validators_. See [Nodes and Networks](https://docs.prylabs.network/docs/concepts/nodes-networks) for a beginner-friendly introduction to Ethereum's node types.
 [^4]: When our `VendingMachine` contract is deployed to Ethereum, it'll be hosted by Ethereum's decentralized network of nodes. Generally speaking, we won't be able to modify the contract's code after it's deployed.
 [^5]: To learn more about how Ethereum wallets work, see [Ethereum.org's introduction to Ethereum wallets](https://ethereum.org/en/wallets/).
-[^6]: Visit the [Gentle Introduction to Arbitrum](../intro/intro.md) for a beginner-friendly introduction to Arbitrum's rollup protocol.
+[^6]: Visit the [Gentle Introduction to Arbitrum](../intro/intro.mdx) for a beginner-friendly introduction to Arbitrum's rollup protocol.
 
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