Update the supported Language/platforms list

[hyangah]

The default image supports now more languages and platforms.
https://github.com/microsoft/vscode-dev-containers/tree/master/containers/codespaces-linux

Why: having up-to-date supported language list is good.

What's being changed: List of supported language. Copy-and-pasted from the codespaces-linux readme.

Check off the following:

• All of the tests are passing.
• I have reviewed my changes in staging. (look for the deploy-to-heroku link in your pull request, then click View deployment)
• For content changes, I have reviewed the localization checklist
• For content changes, I have reviewed the Content style guide for GitHub Docs.

[welcome]

Thanks for opening this pull request! A GitHub docs team member should be by to give feedback soon. In the meantime, please check out the contributing guidelines.

[janiceilene]

Thanks so much for opening a pull request @hyangah! These changes look great ⚡ I'll update the branch and get this merged once tests are passing 🍏

[github-actions]

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