Explain config.txt modification for AIY VoiceHat V1

[DeathByDenim]

In the list of supported audio hardware for the AIY VoiceHat V1, it currently just says that the hardware is supported with a /boot/config.txt modification. It would be great if it could say what that modification should be. It took me quite a while to figure that one out from other sources.
https://github.com/OpenVoiceOS/community-docs/blob/bafacb20b008e3cfd218e2ff58b82c10739a4ba3/docs/011-hardware_audio.md?plain=1#L44

Additionally, the path is no longer /boot/config.txt, but rather /boot/firmware/config.txt.

For reference, the line to add to the config.txt file is:

dtoverlay=googlevoicehat-soundcard

Optionally, disable the default audio source as well by commenting out or removing dtparam=audio=on.