chore(deps): bump @primer/gatsby-theme-doctocat in /docs (#2414)

Bumps @primer/gatsby-theme-doctocat from 4.1.0 to 4.2.0.

---
updated-dependencies:
- dependency-name: "@primer/gatsby-theme-doctocat"
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: Josh Black <joshblack@github.com>