Fix typo in ADVANCED.md

[kaklakariada]

Thank you for this sophisticated library and the helpful documentation!

I found a minor typo in the documentation.

[devinrsmith]

Thanks for the kind words @kaklakariada - sorry it's taken this long for me to get back to this. We had a missing CLA workflow on this repo that I've now remedied. Going forward in the future the process will be more automated - but as of now, to merge this PR we'll need one of:

• Sign the CLA vs the temporary PR CLA assistant workaround #111
• Create and push a new commit to this PR (an empty commit, a rebase, or merge from main should all work), and then accept the new CLA dialog that shows up here

Thanks for your contribution :)