[DOCS] Fixed broken link to forecast API
[DOCS] Fixed broken link to forecast API

Original commit: elastic/x-pack-elasticsearch@41d9918459bf02026e5e2fb518f3aaf2baacb63b

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