Corrected aggregation name to match the example (elastic#33786)

Author: ben5556

docs/reference/aggregations/metrics/sum-aggregation.asciidoc

@@ -40,7 +40,7 @@ Resulting in:
 --------------------------------------------------
 // TESTRESPONSE[s/\.\.\./"took": $body.took,"timed_out": false,"_shards": $body._shards,"hits": $body.hits,/]
 
-The name of the aggregation (`intraday_return` above) also serves as the key by which the aggregation result can be retrieved from the returned response.
+The name of the aggregation (`hat_prices` above) also serves as the key by which the aggregation result can be retrieved from the returned response.
 
 ==== Script