[DOCS] Format the clear cache API (elastic/x-pack-elasticsearch#2574)
[DOCS] Format the clear cache API (elastic/x-pack-elasticsearch#2574)

* [DOCS] Format the clear cache API

* [DOCS] Fixed formatting in clear cache API

Original commit: elastic/x-pack-elasticsearch@f3218ce138b97023acb032222a10e6c635957672

vroyer/elassandra,strapdata/elassandra,strapdata/elassandra,strapdata/elassandra,strapdata/elassandra,vroyer/elassandra,vroyer/elassandra,strapdata/elassandra