FAB-16883 fix kafka.rst doc formatting
FAB-16883 fix kafka.rst doc formatting

Change-Id: Iaa8e0ff8d40843b7f33a74a90f0d1ec6696b31b0
Signed-off-by: Jay Guo <91d7eeb83d08be0dc56ea674009c4b53383e15b3@gmail.com>

hyperledger/fabric,manish-sethi/fabric,manish-sethi/fabric-sidedb,manish-sethi/fabric-sidedb,manish-sethi/fabric-sidedb,manish-sethi/fabric-sidedb,binhn/fabric,jimthematrix/fabric,muralisrini/fabric,manish-sethi/fabric-sidedb,stemlending/fabric,manish-sethi/fabric-sidedb,manish-sethi/fabric,muralisrini/fabric,binhn/fabric,hyperledger/fabric,manish-sethi/fabric-sidedb,stemlending/fabric,muralisrini/fabric,binhn/fabric,stemlending/fabric,stemlending/fabric,jimthematrix/fabric