David Turner 380b45b965
Improve docs for search preferences (#32159)
Today it is unclear what guarantees are offered by the search preference
feature, and we claim a guarantee that is stronger than what we really offer:

> A custom value will be used to guarantee that the same shards will be used
> for the same custom value.

This commit clarifies this documentation.

Forward-port of #32098 to `master`.
2018-07-18 12:58:17 +01:00
..
2018-07-13 14:59:11 -04:00
2017-11-15 21:35:54 +11:00
2018-06-28 10:59:35 -04:00