Bump markdownlint to latest version

[travisbeckham]

Currently the Linkerd website uses a version of markdownlint that doesn't check for broken reference links or link fragments. Unfortunately, upgrading to the latest version results in around 1,000 linting errors.

This PR bumps markdownlint to the latest version, and fixes all of the linting errors. A good chunk of the errors were fixed by running Prettier on the content. After that, I manually addressed each error.

My testing notes

When fixing a linting issue manually, I did a search and replace across all versions, so in theory, if one version of the doc is ok, the other versions are ok too.

When testing, I scanned through each code change in the 2-edge docs and the blog, and did a visual scan of the rendered page in the 2.19 docs and the last year of blog posts. I also searched for every bash and yaml codeblock in 2-edge and the blog and scanned the formatting.

[Copilot]

Pull Request Overview

This PR upgrades markdownlint to the latest version and fixes approximately 1,000 linting errors that were identified across the Linkerd website documentation. The changes primarily involve text reformatting to comply with updated linting rules, including proper line wrapping, consistent spacing around notes and code blocks, and fixing markdown formatting issues.

Key Changes:

• Updated markdownlint to a version that checks for broken reference links and link fragments
• Applied Prettier formatting to content
• Manually fixed remaining linting errors across all documentation versions
• Ensured consistency in markdown formatting including proper spacing around shortcodes, correct list formatting, and appropriate line breaks

Reviewed Changes

Copilot reviewed 224 out of 1190 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
linkerd.io/content/2.11/tasks/canary-release.md	Fixed line wrapping, spacing around notes, and italic formatting
linkerd.io/content/2.11/tasks/books.md	Reformatted long lines and adjusted spacing
linkerd.io/content/2.11/tasks/automatically-rotating-webhook-tls-credentials.md	Fixed line breaks and note formatting
linkerd.io/content/2.11/tasks/automatically-rotating-control-plane-tls-credentials.md	Improved line wrapping and note spacing
linkerd.io/content/2.11/tasks/automatic-failover.md	Reformatted text for better line length
linkerd.io/content/2.11/tasks/adding-your-service.md	Fixed line wrapping and note formatting
linkerd.io/content/2.11/reference/service-profiles.md	Added empty lines around keyval blocks for consistency
linkerd.io/content/2.11/reference/proxy-metrics.md	Converted asterisk lists to hyphen lists and improved formatting
linkerd.io/content/2.11/reference/proxy-log-level.md	Reformatted list items and improved line breaks
linkerd.io/content/2.11/reference/proxy-configuration.md	Fixed quote consistency and line wrapping
linkerd.io/content/2.11/reference/iptables.md	Removed markdown disable comments and improved table formatting
linkerd.io/content/2.11/reference/extension-list.md	Fixed line wrapping for better readability
linkerd.io/content/2.11/reference/cluster-configuration.md	Improved line breaks for long sentences
linkerd.io/content/2.11/reference/cli/viz.md	Fixed line wrapping and improved text flow
linkerd.io/content/2.11/reference/cli/profile.md	Reformatted long lines
linkerd.io/content/2.11/reference/cli/inject.md	Fixed italic formatting
linkerd.io/content/2.11/reference/cli/authz.md	Improved line breaks
linkerd.io/content/2.11/reference/cli/_index.md	Fixed italic formatting
linkerd.io/content/2.11/reference/authorization-policy.md	Added spacing around keyval blocks and improved formatting
linkerd.io/content/2.11/reference/architecture.md	Converted asterisk lists to hyphen lists
linkerd.io/content/2.11/overview/_index.md	Fixed line wrapping and italic formatting
linkerd.io/content/2.11/getting-started/_index.md	Improved formatting and note spacing throughout
linkerd.io/content/2.11/features/*.md	Various formatting improvements including line wrapping, note spacing, and list formatting
linkerd.io/content/2.10/tasks/*.md	Applied similar formatting fixes as 2.11 version

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

[kflynn]

Let's go ahead and land this. It's literally impossible for a human to review, but skimming it makes me feel like we're mostly looking at line-wrapping and I'm OK with that.

🤞 🙂 Ship it!

[cratelyn]

ah thank you, @travisbeckham!