Mentioning an account with dot in username doesn't work
💡 Summary
I was trying to mention @[email protected], but it generated a mention for @[email protected]
🥰 Expected Behavior
Mentions do not stop at dots in usernames.
🤬 Actual Behavior

📌 Environment
Misskey version: 12.117.1 Your OS: Gentoo Linux Your browser: Firefox 91.11.0esr
Related to https://github.com/misskey-dev/misskey/issues/8503#issuecomment-1102543051
Came across this issue while looking into Bridgy Fed. It uses the domain name as the user name by default (e.g. @[email protected]), so it is difficult to interact with accounts on that service from Misskey.
🔥
mfm.jsの問題?
mfm.jsの仕様ですね。 https://github.com/misskey-dev/mfm.js/blob/develop/docs/syntax.md#mention
1文字以上。
A~Z 0~9 _ -が含められる。
1文字目と最後の文字は-にできない。
とのこと。