[DOCS] Note assumptions for shard size and count recommendations (#76353)
[DOCS] Note assumptions for shard size and count recommendations (#76353)

On the "Size your shards" page, the shard size recommendation assumes a time
series use case. Similarly, users shouldn't count nearly empty and rarely used
Enterprise Search system indices against the recommended shard count limit.

Closes #76328.
GlenRSmith/elasticsearch,GlenRSmith/elasticsearch,GlenRSmith/elasticsearch,GlenRSmith/elasticsearch,GlenRSmith/elasticsearch