The @-mention detection regex now recognizes CJK punctuation marks (。、？！) as valid word boundaries, improving mention detection in Chinese, Japanese, and Korean text. Previously, typing @file。 wouldn't trigger autocomplete, but now it does.
Evidence
CJK regex patterns (search for "\u3002\u3001\uFF1F\uFF01")
Strings lifted out of the shipped bundle, so the claim above can be checked against them.
