add note on cheatcodes

Author: zerosnacks

CONTRIBUTING.md

@@ -89,8 +89,12 @@ forge test -vvv
 
 #### Adding cheatcodes
 
+Please follow the guide outlined in the [cheatcodes](https://github.com/foundry-rs/foundry/blob/master/docs/dev/cheatcodes.md#adding-a-new-cheatcode) documentation of Foundry.
+
 When making modifications to the native cheatcodes or adding new ones, please make sure to run [`./scripts/vm.py`](./scripts/vm.py) to update the cheatcodes in the [`src/Vm.sol`](./src/Vm.sol) file. This script will automatically generate the cheatcodes from the [`cheatcodes.json`](https://raw.githubusercontent.com/foundry-rs/foundry/master/crates/cheatcodes/assets/cheatcodes.json) file.
 
+It is possible that the resulting [`src/Vm.sol`](./src/Vm.sol) file will have some changes that are not directly related to your changes, this is not a problem.
+
 #### Commits
 
 It is a recommended best practice to keep your changes as logically grouped as possible within individual commits. There is no limit to the number of commits any single pull request may have, and many contributors find it easier to review changes that are split across multiple commits.