"See also" links are not automatically generated for reference pages in sub-subcategories

Normally, links are automatically added to the "See also" section for all other pages in the same subcategory. However, this is not being done for the Serial, Stream, Keyboard, and Mouse function reference pages. Those only have links to the other pages in their subcategory when those links have been manually added.

I originally thought this was related to those pages being an extra subcategory down, but now I see that the automatically generated "See also" links work fine for the String reference pages.

Reference:
https://github.com/arduino/reference-en/blob/87a3a6763645125f00ad649d803a6d84f0a8e549/AsciiDoc_sample/Reference_Terms/AsciiDoc_Template-Single_Entity.adoc#L120

Start with AsciiDoc_sample/Reference_Terms/AsciiDoc_Template-Single_Entity.adoc around the referenced "See also" section, then compare how automatic links work for String pages versus the Serial, Stream, Keyboard, and Mouse reference pages. Done means those sub-subcategory pages receive the expected links without manually added entries.

Written by the indexing model from the issue text.