fix(docs): use correct prefix for docs (#11018)

Link to lifecycle documentation is missing `/docs` prefix from API specification. Add prefix to fix broken link.

<!--
  Have any questions? Check out the contributing docs at https://gatsby.app/contribute, or
  ask in this Pull Request and a Gatsby maintainer will be happy to help :)
-->

## Description

<!-- Write a brief description of the changes introduced by this PR -->

## Related Issues

<!--
  Link to the issue that is fixed by this PR (if there is one)
  e.g. Fixes #1234, Addresses #1234, Related to #1234, etc.
-->