[DOCS] Add ML geographic functions (elastic/x-pack-elasticsearch#1357)
[DOCS] Add ML geographic functions (elastic/x-pack-elasticsearch#1357)

* [DOCS] Add ML geographic functions

* [DOCS] Add script_fields info to ML geo functions

* [DOCS] Remove summary count from ML geographic functions

* [DOCS] Added example title to geographic functions

* [DOCS] Remove list from ML geographic functions

Original commit: elastic/x-pack-elasticsearch@a8e495657fbbe794434f6baa572e3777707d6b58

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