Add caveat for the priority fee

pages/stack/transactions/fees.mdx

@@ -52,7 +52,8 @@ Read more about the base fee in the [Ethereum.org documentation](https://ethereu
 Just like on Ethereum, OP Mainnet transactions can specify a **priority fee**.
 This priority fee is a price per unit of gas that is paid on top of the base fee.
 For example, if the block base fee is 1 gwei and the transaction specifies a priority fee of 1 gwei, the total price per unit of gas is 2 gwei.
-The priority fee is an optional component of the execution gas fee and can be set to 0.
+The priority fee is an optional component of the execution gas fee and can technically be set to 0.
+However, while EIP-1559 does not define a minimum priority fee, certain wallets and mempool implementations (like Geth) may enforce a minimum value. Geth, for example, typically hardcodes a minimum of 1 wei but defaults to a configurable minimum of around 1 gwei..
 
 **The OP Mainnet sequencer will prioritize transactions with a higher priority fee** and execute them before any transactions with a lower priority fee.
 If transaction speed is important to your application, you may want to set a higher priority fee to ensure that your transaction is included more quickly.