Support non-ASCII identifiers in syntax highlighting

[Alphare]

rust-lang/rust#83799 has been stabilized in 1.53, which means that my first name is now a valid Rust identifier. While this is great news, turns out that only rapha in raphaël is highlighted as a function name.

I am not sure how this is implemented now, but I suspect the regex needs to be adjusted to accept all valid unicode characters under this new feature.

[shepmaster]

You will need to submit a pull request to the Ace editor.

[Alphare]

Sorry, I forgot about this. Will do, thanks. :)

[Alphare]

Opened ajaxorg/ace#4519, thanks.

[shepmaster]

I like to leave these open to keep tabs on things we will need to update eventually. 😉

[camelid]

Looks like the upstream issue has been fixed!