minor issue when when doing a full reindex in queue mode

[goromlagche]

Describe the bug
Not necessarily a bug, but there are some gotchas when trying to do a full reindex with queue mode,

e.g.

Product.reindex(mode: queue)
Searchkick::ProcessQueueJob.perform_later(class_name: "Product")

Does not work as intended.

this does

Product.reindex(mode: queue)
Searchkick::ProcessQueueJob.perform_later(class_name: "Product", index_name: "new_product_index_with_timestamp")

My guess is

searchkick/lib/searchkick/record_indexer.rb

Line 51 in a682677

index.reindex_queue.push_records(records)

in here index is the raw index. reindex_queue.send(:redis_key) will return new_product_index_with_timestamp

But when process queue job pulls in the data

searchkick/lib/searchkick/process_queue_job.rb

Line 11 in a682677

record_ids = index.reindex_queue.reserve(limit: limit)

it uses alias.

It will be good to update to fix the code path to always use alias name. Or update the readme with a note.