Rename Hige_(Hige2) to Hige_Bear

BUR #49819 has been rejected.

rename hige_(hige2) -> hige_bear

Basically, Hige_(hige2) is the same artist as Hige_Bear
Compare, for instance, the following post on Hige_bear 's Misskey (warning: explicit) and post #2789883 , made by Hige_(hige2)

That's not how we merge artist tags. See topic #7713.

The bulk update request #49819 (forum #395223) has been rejected by @evazion.