[docs] POST /_aliases remove_index action only works on concrete indices

[rudolf]

$ curl -X PUT "elastic:changeme@localhost:9200/.kibana_1"
{"acknowledged":true,"shards_acknowledged":true,"index":".kibana_1"}
$ curl -X PUT "elastic:changeme@localhost:9200/.kibana_1/_alias/.kibana"
{"acknowledged":true}
$ curl -X POST "elastic:changeme@localhost:9200/_aliases" -H 'Content-Type: application/json' -d'
{
  "actions" : [
    { "remove_index": { "indices": ".kibana" } }
  ]
}
'
{"error":{"root_cause":[{"type":"illegal_argument_exception","reason":"The provided expression [.kibana] matches an alias, specify the corresponding concrete indices instead."}],"type":"illegal_argument_exception","reason":"The provided expression [.kibana] matches an alias, specify the corresponding concrete indices instead."},"status":400}

[elasticmachine]

Pinging @elastic/es-docs (>docs)

[jrodewig]

LGTM. I'm going to incorporate a minor edit.

[rudolf]

@jrodewig I missed that the delete API has the same behaviour so +1 for your edit. Maybe we should update my second edit as well:

remove_index is just like <> but will only remove a concrete index.

to become:

remove_index is just like <> and will only remove a concrete index.

[jrodewig]

Thanks for pointing that out @rudolf. I'll handle that as part of a follow-up PR or commit.

[jrodewig]

Updated the callout text with c7a11b5 and backported to the appropriate branches.