review the regex for hashtags

currently a hashtag is "any character that does not match [\s.,\u2063!?'"#:/[\]【】()「」（）<>]

weird effects:

• | does not terminate a hashtag
• "zero-width space" does not terminate a hashtag (\s matches very few characters: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Lexical_grammar#white_space or https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Lexical_grammar#line_terminators)

maybe we want something with \p{White_Space} and \p{Word_Break=???}