Remove description from example frontmatter

[emilk]

What

We were duplicating descriptions for no gain. Indeed, we were showing them double on https://www.rerun.io/examples/:

This PR simplifies things a lot, and unifies the look.

The duplicated description is fixed in https://github.com/rerun-io/landing/commit/af157fa42788128a40d6395bf5a16dc0d4aa87b8

The result looks like this:

An added bonus is that the description now can have hyperlinks in it.

I also updated the template README.md:s so they can be used as templates.

Checklist

• I have read and agree to Contributor Guide and the Code of Conduct
• I've included a screenshot or gif (if applicable)
• I have tested the web demo (if applicable):
  • Using newly built examples: rerun.io/viewer
  • Using examples from latest main build: rerun.io/viewer
  • Using full set of examples from nightly build: rerun.io/viewer
• The PR title and labels are set such as to maximize their usefulness for the next release's CHANGELOG
• If applicable, add a new check to the release checklist!

• PR Build Summary
• Recent benchmark results
• Wasm size tracking

[github-actions]

Deployed docs

Commit	Link
8e10a12	https://landing-je4r9zd7f-rerun.vercel.app/docs