Fix up changelog and add entry in alerts section for #1421

[apiology]

The calculator changelog formatting was not showing up correctly, and
there was no entry in the alerts section for the
covid19-projections.com update.

[netlify]

✅ Deploy Preview for microcov ready!

Name	Link
🔨 Latest commit	34ff954
🔍 Latest deploy log	https://app.netlify.com/sites/microcov/deploys/638f2881e762ee000803512f
😎 Deploy Preview	https://deploy-preview-1678--microcov.netlify.app/
📱 Preview on mobile	Toggle QR Code... Use your smartphone camera to open QR code link.

---

To edit notification comments on pull requests, go to your Netlify site settings.

[netlify]

✅ Deploy Preview for microcov ready!

Name	Link
🔨 Latest commit	3cd1bb6
🔍 Latest deploy log	https://app.netlify.com/sites/microcov/deploys/638f2fbc6f7d160008853d38
😎 Deploy Preview	https://deploy-preview-1678--microcov.netlify.app
📱 Preview on mobile	Toggle QR Code... Use your smartphone camera to open QR code link.

---

To edit notification comments on pull requests, go to your Netlify site settings.

[codecov]

Codecov Report

Merging #1678 (3cd1bb6) into main (c38457f) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##             main    #1678   +/-   ##
=======================================
  Coverage   55.86%   55.86%           
=======================================
  Files         103      103           
  Lines        2533     2533           
  Branches      528      528           
=======================================
  Hits         1415     1415           
  Misses        967      967           
  Partials      151      151           

Impacted Files	Coverage Δ
src/pages/Calculator.tsx	77.88% <ø> (ø)
src/posts/paper/99-changelog.ts	100.00% <ø> (ø)

📣 We’re building smart automated test selection to slash your CI/CD build times. Learn more