Symbol jump to a line with half-width katakana jumps to incorrect position

[beansmayawait]

If you have something like
let char: char = 'ｱ' // some extra text to jump to
and try to symbol-jump to the text after the ｱ (this is a half-width katakana), the cursor goes 1 position after the correct destination.

Amazing editor, by the way!

[oldaccountdeadname]

If you have something like `let char: char = 'ｱ' // some extra text to jump to` and try to symbol-jump to the text after the ｱ (this is a half-width katakana), the cursor goes 1 position after the correct destination.

Yeah, there are some (many) rough spots around unicode handling of grapheme clusters with more than one codepoint. (In UTF-8, the half-width katakana looks to be 0xE3 0x82 0xA2, which counts for more graphemes than it actually is, thus causing cursor displacement.) There was a similar issue causing the addition of a trailing newline to fail, which was fixed in 10b0290 (PR #243 if I got that hash wrong). I don't think I've got time to fix it right now, but I don't think it would be awfully difficult if you want to take a look and put together a PR.