This is a tracking ticket for updates to driver documentation that is query cache-related.

I suggest not referencing Mongoid query cache from the driver documentation.
Limit behavior documentation would need to be updated when https://jira.mongodb.org/browse/RUBY-2340 is done.
If middleware is added to driver, add documentation for middleware.
Add documentation for explicitly clearing the cache.
Add documentation for disabling query cache in an inner scope from where it's enabled.
Add documentation for using the query cache with transactions (explicitly say that the cache is cleared on transaction commit and abort).
Add documentation for using query cache with aggregations (document that cache key selector field is sometimes a hash and sometimes an array).