Doc importing - some links incorrectly prefix with `/docs`

[ChrisBAshton]

See https://docs.publishing.service.gov.uk/apps/search-api/using-the-search-api.html#returning-specific-document-fields

The field reference link links to: https://github.com/alphagov/search-api/blob/main/docs/config/schema/field_definitions.json

It should actually link to: https://github.com/alphagov/search-api/blob/main/config/schema/field_definitions.json

The markdown used is /config/schema/field_definitions.json. The / should make this root to the repository, rather than root to the Developer Docs.

i.e. /config/foo should translate to https://github.com/alphagov/{repo_name}/blob/main/config/foo. But ./config/foo should translate to https://docs.publishing.service.gov.uk/apps/{repo_name}/config/foo.html

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Zendesk: https://govuk.zendesk.com/agent/tickets/4788958