Fix unicode escape handling in strings
This had been copy-pasted from the kotlin grammar but the two aren't
actually the same. Swift allows shorter escape sequences but requires
them to be enclosed in braces.
Fixes
@@ -233,7 +233,7 @@ module.exports = grammar({
_line_str_escaped_char: ($) =>
choice($._escaped_identifier, $._uni_character_literal),
- _uni_character_literal: ($) => seq("\\", "u", /[0-9a-fA-F]{4}/), // TODO: { }
+ _uni_character_literal: ($) => seq("\\", "u", /\{[0-9a-fA-F]+\}/),
multi_line_string_literal: ($) =>
seq(
