Document client.queryWatermarkOffsets (#215)
Document client.queryWatermarkOffsets (#215)

* Document client.queryWatermarkOffsets

I found myself digging quite long for a solution to this problem.

According to https://github.com/Blizzard/node-rdkafka/pull/170/commits/77bbb7527ba6a46cbfa455b6af6c1275cb43f498#diff-50cfa59973c04321b5da0c6da0fdf4feR441, I believe something like the above would be a correct way of calling the function.

* Use correct properties

* Fix PR comments (Use var convention from rest of README.md)

Blizzard/node-rdkafka,Blizzard/node-rdkafka,Blizzard/node-rdkafka,Blizzard/node-rdkafka