Limits the number of documents in the result set.
This function is useful for setting the limit on a cursor after the cursor is created, but before any
calls to mongoc_cursor_next(). It can also be used to pass a negative limit: The limit parameter to
mongoc_cursor_set_limit is signed, although for backward-compatibility reasons the limit parameter to
mongoc_collection_find() is not.
Calling this function after mongoc_cursor_next() has no effect.
This is not applicable to all cursors. Calling mongoc_cursor_set_limit() on a cursor returned by
mongoc_client_find_databases_with_opts(), mongoc_database_find_collections_with_opts(), or
mongoc_collection_find_indexes_with_opts() will not change the results.