Update index.md

[brandon-braner]

Updated link for PopSql to be an actual link

Description

I noticed the link in the docs to popsql on this page was not correct. Fixed it.

Links

Fixes #[insert issue link, if any]

Writing help

For information about style and word usage, see the style guide

Review checklists

Reviewers: use this section to ensure you have checked everything before approving this PR:

Subject matter expert (SME) review checklist

• [ ] Is the content technically accurate?
• [ ] Is the content complete?
• [ ] Is the content presented in a logical order?
• [ ] Does the content use appropriate names for features and products?
• [ ] Does the content provide relevant links to further information?

Documentation team review checklist

• [ ] Is the content free from typos?
• [ ] Does the content use plain English?
• [ ] Does the content contain clear sections for concepts, tasks, and references?
• [ ] Have any images been uploaded to the correct location, and are resolvable?
• [ ] If the page index was updated, are redirects required and have they been implemented?
• [ ] Have you checked the built version of this content?

[CLAassistant]

All committers have signed the CLA.