Allow non-ASCII characters in emoji names

[JadedCtrl]

Tweaks the emoji shortcode regex to allow non-ASCII alphanumeric characters; this is for internationalization, to allow emoji names to be in languages that don’t fall within ASCII.

[JadedCtrl]

Non-ASCII emoji-names are currently allowed in Pleroma.

This PR was also sent to upstream Mastodon, and rejected on anglocentric grounds:
mastodon#27809
mastodon#28572

[jakkarth]

Sadly not a maintainer here but I'd also enjoy having this functionality.

[ClearlyClaire]

I agree with mastodon#28572 (comment) on the specific example, but I see the value in allowing non-ASCII characters in such identifiers.

Since it's not going to be accepted by upstream Mastodon, I'm not sure it's worth allowing local non-ASCII custom emoji shortcodes, but I think allowing non-ASCII shortcodes for remote custom emoji makes sense. This will prevent copying them as-is, though, so that would require some special handling…

[smiba]

[...] I'm not sure it's worth allowing local non-ASCII custom emoji shortcodes, but I think allowing non-ASCII shortcodes for remote custom emoji makes sense

Keep in mind there are mastodon instances in languages this very moment that do not fit the ASCII character set (Instances in Japanese, Mandarin, Hindi and the list goes on)
It might feel like a useless feature for us in the west as the majority of our languages fit ASCII perfectly fine, but those other languages have no other choice!