Forbid links to localhost with Markdownlint

[teoli2003]

Summary

This happens in #23675

A few links lead to https://localhost:5042/....

These are always erroneous. We should:

• Raises a flaw
• Magically convert them to /... (like we do for https://developer.mozilla.org/)

URL

None that I know.

Reproduction steps

1. Create a Markdown link in a page like [HTMLElement](https://localhost:5042/en-US/docs/Web/API/HTMLElement)
2. Build the page

Expected behavior

A flaw is reported.
The link is transformed into the equivalent of [HTMLElement](/en-US/docs/Web/API/HTMLElement)

Actual behavior

No flaw reported
A broken link.

Device

Desktop

Browser

Chrome

Browser version

Stable

Operating system

Android

Screenshot

No response

Anything else?

I think we can solve this issue by adding an extra alternative at: https://github.com/mdn/yari/blob/main/build/flaws/broken-links.ts#L232

Something similar to:

But for https://localhost[:wxyz]?

If this is the right way, I can create a PR.

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.

[caugner]

Can we add a markdownlint rule like the one for fully-qualified developer.mozilla.org URLs?

content/.markdownlint-cli2.jsonc

Lines 184 to 190 in 0053e22

	{
	"name": "fqdn-moz-links",
	"message": "Don't use developer.mozilla.org for links",
	"search": "](https://developer.mozilla.org/",
	"replace": "](/",
	"skipCode": true
	},

[teoli2003]

Oh yes! Good point. I will do it.

[hamishwillee]

This is a good catch @teoli2003 !