hashtag's link text range is incorrect in the Web UI #9989
Description
After #8447 has been merged, it seems incorrect processing of hashtags including multibyte characters such as the following in WebUI.
https://taruntarun.net/@mayaeh/101557400350655981.json
It recognized the entire "testテスト" as a hashtag, but "テスト" does not become a link.
However, it seems to be no problem with a hashtag composed only of multibyte characters.
Expected behaviour
I think it should be as follows:
https://edge.taruntarun.net/@mayaeh/101557496224395192
Actual behaviour
Steps to reproduce the problem
Post a hashtag combining single byte alphanumeric characters and multibyte characters.
Specifications
Equivalent to master branch