gremlin-go: rename function "extractWithReqArgs" to "extractWithReqArg"
gremlin-go: rename function "extractWithReqArgs" to "extractWithReqArg"

The function "extractWithReqArgs" returns one single request argument.
Therefore, it makes sense to rename it to "extractWithReqArg".

apache/tinkerpop,apache/tinkerpop,apache/tinkerpop,apache/tinkerpop,apache/tinkerpop,apache/tinkerpop,apache/tinkerpop