When building a PR locally, I ran into an issue where the server kept crashing. I ran `yarn kbn clean`, and saw this message in my terminal:
>warn This command is only necessary for the rare circumstance where you need to recover a consistent state when problems arise. If you need to run this command often, >please let us know by filling out this form: https://ela.st/yarn-kbn-clean

I think it makes sense to add this information to the docs so that if users are reading it, they know that this command is not typically necessary.