[Update] Disamb. for Single Name Performers

[AdultSun]

It has already been well-established that single-name performers like Jane or John need to have some disambiguation attached, even if there are no other performers currently known to share that name on StashDB or elsewhere. However, we don't have anything in the guidelines to clarify this yet.

I expect that this will be a quick and easy addition. I also expect that we'd be able to approve the unofficial language (as described above) without much pushback or alteration.

[AdultSun]

New section has been merged into the guidelines, but still needs official approval. Issue has been updated accordingly.