Add note about size being per shard here

It seems the current note via the comment is too less intrusive for people to notice and it leads to strange results otherwise.

docs/java-api/search.asciidoc

@@ -68,6 +68,10 @@ do {
     scrollResp = client.prepareSearchScroll(scrollResp.getScrollId()).setScroll(new TimeValue(60000)).execute().actionGet();
 } while(scrollResp.getHits().getHits().length != 0); // Zero hits mark the end of the scroll and the while loop.
 --------------------------------------------------
+[NOTE]
+====
+The size-parameter is per shard, so if you run a query against multiple indices (leading to many shards being involved in the query) the result might be more documents per execution of the scroll than you would expect!
+====
 
 [[java-search-msearch]]
 === MultiSearch API