Update Refcount-related Docs

[ericsnowcurrently]

Documentation

PEP 683 includes some docs changes that should help narrow expectations about refcount semantics. Those changes shouldn't need to wait for the PEP.

I'd be interested in backporting these changes as far back as possible.

Linked PRs

• gh-98154: Clarify Usage of "Reference Count" In the Docs #107552
• [3.12] gh-98154: Clarify Usage of "Reference Count" In the Docs (gh-107552) #107752
• [3.11] gh-98154: Clarify Usage of "Reference Count" In the Docs #107753
• [3.10] gh-98154: Clarify Usage of "Reference Count" In the Docs #107754