Add include_docs to DocumentFetchParams typescript definition

[sziladriana]

Add include_docs to DocumentFetchParams typescript definition, as mentioned in https://github.com/apache/couchdb-nano/tree/2d4bd719e4f08915ed9c0ef7953e901391ce4239#dbpartitionedlistpartitionkey-params-callback

Checklist

• [x] Code is written and works correctly;
• [ ] Changes are covered by tests;
• [x] Documentation reflects the changes;

[sziladriana]

Hello, can this be released? I saw several other PRs merged but no new release in the meantime.