i18n: locale name without subtag

Hello!
The Occitan locale has a subtag for the dialect.
I was wondering what happends if the code calls dayjs with only the locale iso code "oc".
I think it will just not load the locale at all.
Could we create a "oc" file that points at oc-lnc? Or just rename oc-lnc to "oc".
Catalan has not several dialects variations here, maybe Occitan should do the same.
Although, since the creation of the Occitan locale, an official tag has been approved and for lengadocian it's oc-lengadoc

Start by checking how Day.js resolves locale codes and how the existing Occitan locale is loaded. Compare the proposed "oc" mapping with the official "oc-lengadoc" tag, then verify that calls using only "oc" load the intended locale consistently.

Written by the indexing model from the issue text.