[DOCS] Update get datafeed statistics API output (elastic/x-pack-elasticsearch#1678)
[DOCS] Update get datafeed statistics API output (elastic/x-pack-elasticsearch#1678)

Original commit: elastic/x-pack-elasticsearch@7e65102ac0101272eda4c22d3a725aecde06a8fc

gingerwizard/elasticsearch,coding0011/elasticsearch,vroyer/elassandra,uschindler/elasticsearch,gingerwizard/elasticsearch,nknize/elasticsearch,vroyer/elassandra,HonzaKral/elasticsearch,uschindler/elasticsearch,strapdata/elassandra,robin13/elasticsearch,gfyoung/elasticsearch,strapdata/elassandra,coding0011/elasticsearch,scorpionvicky/elasticsearch,robin13/elasticsearch,HonzaKral/elasticsearch,uschindler/elasticsearch,uschindler/elasticsearch,GlenRSmith/elasticsearch,nknize/elasticsearch,nknize/elasticsearch,nknize/elasticsearch,HonzaKral/elasticsearch,strapdata/elassandra,coding0011/elasticsearch,gingerwizard/elasticsearch,robin13/elasticsearch,GlenRSmith/elasticsearch,scorpionvicky/elasticsearch,strapdata/elassandra,gingerwizard/elasticsearch,gfyoung/elasticsearch,GlenRSmith/elasticsearch,scorpionvicky/elasticsearch,coding0011/elasticsearch,robin13/elasticsearch,strapdata/elassandra,GlenRSmith/elasticsearch,gingerwizard/elasticsearch,nknize/elasticsearch,scorpionvicky/elasticsearch,gingerwizard/elasticsearch,gfyoung/elasticsearch,uschindler/elasticsearch,HonzaKral/elasticsearch,coding0011/elasticsearch,vroyer/elassandra,robin13/elasticsearch,gfyoung/elasticsearch,gfyoung/elasticsearch,GlenRSmith/elasticsearch,gingerwizard/elasticsearch,scorpionvicky/elasticsearch