Outdated documentation?

[Quadragintillion]

Your Godot version: 4.3

Issue description: The page for making custom AudioStreams seems to be outdated

URL to the documentation page: https://docs.godotengine.org/en/stable/contributing/development/core_and_modules/custom_audiostreams.html

Trying to follow along and then building tells me that core/reference.h, core.resource.h, and core/print_string.h all don't exist. Godot builds fine without my custom module. I copied and pasted the exact code from the guide, only changing the names of the files and classes.