Update extensions.json to add Tables+

[MissingLinkDev]

Make sure that your submission has the following:

• [x ] A link to the raw github markdown file with a YAML front matter definition containing:
  • [x ] The title of your extension
  • [x ] A description of your extension
  • [x ] The author
  • [ x] A hero image
  • [x ] An icon
  • [ x] Tags (these will help with your extension's discoverability)
  • [x ] A link to your extensions manifest

Please, go through these steps before you submit a PR.

• [x ] You have done your changes in a separate branch.

• [x ] You have a descriptive commit message with a short title (first line).

• [x ] You have only one commit (if not, squash them into one commit).

• [x ] Your pull request MUST target the main branch on this repository.

• [x ] Your pull request puts your extensions details as the last entry in the extensions.json file