Remove (most) of the limits on tags

[calpaterson]

Brief overview

AS AN enthusiastic tagger

I WANT to be able to put all sorts of odd characters in my tags

SO THAT I can use tags according to my own idiosyncratic designs

Additional details

l0b0 has suggested "arbitrary UTF-8 bytes" which is a bit more than I'd like to do for this story, but I would like to at least allow:

• emoji
• non-alpha characters in the base ascii set, eg :\*% etc but not / or @ which require a little more thought because of the potential for hijinks when they appear in a url
• unicode alphanumeric characters

[l0b0]

Some more specific use cases I've actually perpetrated:

• ★★★★★ ratings
• Various programming syntax. This is particularly useful, since it's impossible to web search for strings like $' or <<<.
• Ring of commas
• Backslash