add updated cache.evict args to docs (#5818)
add updated cache.evict args to docs (#5818)

* add updated cache.evict args to docs

* Slight wording tweaks

Co-authored-by: Hugh Willson <a6c5230a10c458028ff1bd5985dd47c394028d47@octonary.com>

apollostack/apollo-client,apollostack/apollo-client,apollographql/apollo-client,apollographql/apollo-client,apollostack/apollo-client