Let's approach this part by part.
Does [ascii-art] mean only ASCII?
Yes, otherwise it should be tagged character-art or similar.
Whilst this is almost true
If you think a tag wiki needs improvement, please improve it.
Would I be justified in re-writing this so that it allows character-art in general?
If the tag was named character-art instead of [ascii-art], that would've been a great idea.
I'd propose the following:
- Create a new tag character-art.
- Synonimize ascii-art to character-art or half the users will stick the wrong tag on the question. ASCII art is a wide-spread (and often mis-used IMO) name. People will look for the tag and people will use both tags if we don't somehow smash them together.
- Put your suggested text in the character-art description.
Either that, or simply rename ascii-art to character-art, edit the tag description as suggested afterwards. ascii-art isn't used much as a tag after all and it's arguable it even needs it's own tag. Should the tag ever be created again we'll cross that bridge when we come to it.
I'm ambivalent about which route is better.