Migrate accessibility rule a11y_link_has_href from dotcom to erblint-github

[bolonio]

Context

The motivation of erblint-github is to open-source our accessibility rules so non-GitHub people can benefit from them, have a space to provide comprehensive rule documentation, and also allow rules to be shared between Rails projects.

This PR migrates the accessibility rule a11y_link_has_href from dotcom to erblint-github

Related issue

• https://github.com/github/accessibility/issues/1293

[khiga8]

Looks great 🚀

[khiga8]

I forgot to mention this in the issue but if you're up for it, it would be good to convert this (and other non-counter rules) to a Counter as you migrate them.

The only difference implementation wise is:

• rule_disabled? becomes counter_correct?
• we add this def autocorrect method
• update the rule name to end with Counter.

A Counter will always flag new violations that are added to the file (since erblint:disable completely disables the lint rule for the file). You can read more about the difference here! If you think it's out of scope we can save this for a follow-up issue as well!

[accessibility-bot]

👋 Hello and thanks for pinging us! An accessibility first responder will review this soon.

• 💻 On PRs for our review: please provide a review environment with steps to validate, screenshots (with alt text), or videos demonstrating functionality we should be checking. This will help speed up our review and feedback cycle.
• ⚠️ If this is urgent, please visit us in #accessibility on Slack and tag the first responder(s) listed in the channel topic.

[khiga8]

Thanks for converting this to a counter 🎉