Fix potentially broken references in the documentation

[moe-ad]

As part of recently completed tasks in #296, it was decided to remove reference labels found in module docstrings (#1975). These labels became broken because section titles had been removed from the module docstrings as a fix to ensure icons properly render in the api documentation (#1971).

This purpose of this issue is to address the removed reference labels.

[PProfizi]

Hi @moe-ad,

are current references in the doc to these modules still going to work?

[moe-ad]

@PProfizi, sorry I didn't catch this earlier. The stable version of the doc is not impacted.
And now a PR(#2006) has been created to fix this issue.