Add examples to api/1/raw-extrinsic-metadata/swhid/authorities/doc/

From this API endpoint documentation I'm not sure if full SWHIDs are accepted. If yes, more examples should be provided. If no or not yet, this should be clarified.

Here is the direct link to the endpoint: https://archive.softwareheritage.org/api/1/raw-extrinsic-metadata/swhid/authorities/doc/

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Migrated from T3478 (view on Phabricator)