Emphasis marks do not skip tilde

[xfq]

https://drafts.csswg.org/css-text-decor-3/#text-emphasis-style-property

The list includes the Unicode P* general category, but not the Sm general category. U+FF5E and U+007E should also be skipped per https://www.w3.org/International/clreq/#id84 and https://www.w3.org/International/clreq/#id85 .

[kidayasuo]

Initially commented here: w3c/jlreq-d#80 (comment)

We discussed this at the JLReq TF meeting on 2025-03-11 (meeting notes to be posted soon). The conclusion was as follows:

1. Although it is common practice not to attach emphasis marks to punctuation, this should be treated as a guideline rather than a strict rule. If an author or editor intentionally chooses to apply emphasis marks to any character, it should be allowed. Therefore, this rule should not be enforced.
2. As a convenience feature, it may still be helpful for systems to automatically skip certain character classes (such as punctuation). This makes it easier for users to select a full range of text without worrying about fine details, while still generally aligning with common practice.