Do not raise "Anchor not lowercase" flaw when the anchor is a fragment directive

[teoli2003]

Summary

Yari raises an Anchor not lowercase flaw when internal URL anchors have uppercase letters. This is good, and it allows us to detect and fix them (we have fixed almost all of them).

Text fragments is an extension to the anchor system that allows linking to a portion of text in a web document. Unlike traditional anchors, they are not set by the web page author.

We have two links to demonstrate this new feature on this page. They are flagged as flaws and shouldn't be.

URL

https://developer.mozilla.org/en-US/docs/Web/Text_fragments

Reproduction steps

1. Go to the page (in a locally-run instance of mdn/content displaying flaws at the top)
2. Look at the flaws: here they are

Expected behavior

No Anchor not lowercase flaw for anchors starting with the fragment directive (:~:).

Actual behavior

An Anchor not lowercase flaw listed for each anchor starting with the fragment directive (:~:).

Device

Desktop

Browser

Chrome

Browser version

Stable

Operating system

Android

Screenshot

Anything else?

To fix this, we should always prevent fragments starting with :~: from raising a flaw.

Validations

• I have read the Community Participation Guidelines.
• I have verified that there isn't already an issue that reports the same bug to avoid creating a duplicate.
• I have checked that this is a concrete bug. For Q&A open a GitHub Discussion.