fix broken M-16-21 link

[joel-trout-dds]

Thanks for submitting a pull request! Below are a few things you can do to help us more quickly review your changes.

Checklist

I have…

• [x] run the application locally (./scripts/serve) and verified that my changes behave as expected.
• [ ] run the build process locally (./scripts/build) and make sure it builds correctly.
• [ ] run the test suite (./scripts/test) and verified that all tests pass.
• [ ] summarized below my changes and noted which issues (if any) this pull request fixes or addresses.
• [ ] thoroughly outlined below the steps necessary to test my changes.
• [ ] attached screenshots illustrating relevant behavior before and after my changes.
• [ ] read, understand, and agree to the terms described in CONTRIBUTING.md.
• [ ] added my name, email address, and copyright date to CONTRIBUTORS.md.

Summary of Changes

This pull request…

• Summarize change number one.
• Summarize change number two.
• etc. etc. etc.

Testing

To verify the changes proposed in this pull request…

1. Describe testing step one.
2. Describe testing step two.
3. etc. etc. etc.

Screenshots

Attach relevant before and after screenshots here.