fixrule(aria_descendant_valid): When the contained role is code, report a recommendation

[tombrunet]

Summary

• New or modified checker rule(s)
• New or modified help files
• Other (Provide information)

This PR is related to the following issue(s):

• Fixes [Feature]: Consider downgrading the case of "code" in "button" to recommendation #2539

Testing reference:

• Existing automated tests

I have conducted the following for this PR:

• I validated this fix in my local env and provided testing information above
• I understand that the title of this PR will be used for the next release notes.
• I added I agree to the DCO at https://developercertificate.org/ for this contribution. as a comment after creating the pull request.

Assets to aide review attached

• Links to design artifacts
• Links to video walkthrough of user experience
• Other

Definition of Done

• Peer review complete
• Secondary review complete
• Staging deployment verified

[tombrunet]

I agree to the DCO at https://developercertificate.org/ for this contribution.

[chrisgrimley]

I haven't tested the code but the logic at least makes sense to me @tombrunet.