Update example query

[jazairi]

What does this PR do?

Changes the example query from 'kerbal' to 'spaceflight'.

Helpful background context

Due to an issue with the Aleph export, 'kerbal' does not currently return results.

How can a reviewer manually see the effects of these changes?

In the PR build (or local dev environment), the changes should be visible in the example query:

{
  search(searchterm: "spaceflight") {
    records {
      sourceLink
      title
      links {
        text
        url
      }
    }
  }
}

Requires Database Migrations?

NO

Includes new or updated dependencies?

NO