[DOCS] rewrite -> fuzzy_rewrite in match query
Fixed typo
[TEST] add a test that explicitly verifies no duplicates are created
we do this test in other places in ES, but no dedicated test for it. This test was born out of the auto generate id work, but we should have this test regardless if it gets in or not
Add REST API spec for /_search_shards endpoint

Also adds REST test for /_search_shards

Closes #5907