Change the category of Tsukigi's "Twitter-san" into character

BUR #35117 has been approved by @evazion.

category twitter-san -> character
create alias twitter-san -> twitter-san_(tsukigi)
remove alias twitter-san -> twitter-san_(tsukigi)

For whatever reason, the original character Twitter-san by Tsukigi was categorized as a copyright tag. Since this character has a distinct design and even has a Pixivpedia entry about it. I think this should be separated from the other Twitter gijinkas by given a proper qualifier.

As a side note, there exists a tag called Twitter-san (character), but this seems to cover any other Twitter gijinka, not just Tsukigi's. Therefor I think a cleanup is needed to separate these design from each other. There is also Twit-tan, which is described as a "mascot" for Twitter (even tho it doesn't feel like an official one).

The bulk update request #35117 (forum #328623) has been approved by @evazion.

BingusX said:

As a side note, there exists a tag called Twitter-san (character), but this seems to cover any other Twitter gijinka, not just Tsukigi's. Therefor I think a cleanup is needed to separate these design from each other. There is also Twit-tan, which is described as a "mascot" for Twitter (even tho it doesn't feel like an official one).

Based on Pixpedia and the fact that the designs in the tag are all largely uniform (aside from one that I've banished to Twitter-san (character)), it seems that this is a specific gijinka that someone made (and the usage of "mascot character" in the wiki meant more like OS-tan than official), meaning it should probably get a qualifier. We'd need to figure out who made the design though.