Kakoune: Adds and fixes ident highlighters, adds static_words and updates the keywords and builtins

[allenyade]

• Adds an "asterisk" highlighter which will highlight an asterisk in [*] and [<*>]
• Splits the ident highlighter in const and type highlighters to not highlight some edge cases
• Gets rid of all the uses of \w in regex pattern (it includes UTF-8 characters c3c will not accept as valid idents, therefore they should not be highlighted)
• Removes the prefixes from the %sh section variables and adds them in the highlighters declarations directly
• Updates the variables from the %sh section and adds builtins from std::core::env so they get properly highlighted

[lerno]

Do we have anyone who could review this one?