chore(deps): migrate from eslint-plugin-markdown to @eslint/markdown

[rubiesonthesky]

PR Checklist

• Addresses an existing open issue: fixes 🛠 Tooling: use @eslint/markdown #2499
• That issue was marked as status: accepting prs
• Steps in CONTRIBUTING.md were taken

Overview

The other package has been deprecated for some time. Take the recommended package into use.

🐙

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 74.22%. Comparing base (157f1f7) to head (ce8ed02).

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #2500   +/-   ##
=======================================
  Coverage   74.22%   74.22%           
=======================================
  Files         169      169           
  Lines        2875     2875           
  Branches      721      721           
=======================================
  Hits         2134     2134           
  Misses        508      508           
  Partials      233      233           

Flag	Coverage Δ
mutation	66.81% <ø> (ø)
unit	20.93% <ø> (ø)

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[JoshuaKGoldberg]

Swell, thanks! ❤️