Colin Goodheart-Smithe 1efb1aae28
[DOCS] Rewords _field_names documentation (#31029)
* [DOCS] Rewords _field_names documentation

Corrects the language around when we write to `_field_names` and when you might want to disable it given that n recent versions it does not carry the indexing overhead it once did.

Relates to #30862

* Update wording following review
2018-06-04 09:17:11 +01:00
..