MINOR: Escape '<' and '>' symbols in quickstart streams code snippet
MINOR: Escape '<' and '>' symbols in quickstart streams code snippet

This was missing from [an earlier PR](https://github.com/apache/kafka/pull/2247) that escaped these symbols in another section of the doc.

Author: Vahid Hashemian <vahidhashemian@us.ibm.com>

Reviewers: Ewen Cheslack-Postava <ewen@confluent.io>

Closes #2453 from vahidhashemian/doc/escape_lt_gt_in_streams_code

apache/kafka,Chasego/kafka,ErikKringen/kafka,themarkypantz/kafka,sslavic/kafka,noslowerdna/kafka,airbnb/kafka,MyPureCloud/kafka,rhauch/kafka,Ishiihara/kafka,themarkypantz/kafka,lindong28/kafka,mihbor/kafka,sslavic/kafka,guozhangwang/kafka,guozhangwang/kafka,mihbor/kafka,ErikKringen/kafka,MyPureCloud/kafka,Chasego/kafka,ErikKringen/kafka,Ishiihara/kafka,ollie314/kafka,airbnb/kafka,ollie314/kafka,apache/kafka,apache/kafka,sebadiaz/kafka,sebadiaz/kafka,TiVo/kafka,ijuma/kafka,sslavic/kafka,KevinLiLu/kafka,Esquive/kafka,guozhangwang/kafka,sebadiaz/kafka,guozhangwang/kafka,KevinLiLu/kafka,sslavic/kafka,TiVo/kafka,Ishiihara/kafka,TiVo/kafka,lindong28/kafka,KevinLiLu/kafka,ijuma/kafka,richhaase/kafka,richhaase/kafka,airbnb/kafka,apache/kafka,Esquive/kafka,KevinLiLu/kafka,noslowerdna/kafka,ijuma/kafka,MyPureCloud/kafka,noslowerdna/kafka,lindong28/kafka,gf53520/kafka,mihbor/kafka,noslowerdna/kafka,TiVo/kafka,rhauch/kafka,sebadiaz/kafka,rhauch/kafka,airbnb/kafka,lindong28/kafka,richhaase/kafka,ollie314/kafka,themarkypantz/kafka,ollie314/kafka,Chasego/kafka,Chasego/kafka,gf53520/kafka,ijuma/kafka,ErikKringen/kafka,gf53520/kafka,Ishiihara/kafka,themarkypantz/kafka,Esquive/kafka,Esquive/kafka,MyPureCloud/kafka,richhaase/kafka,gf53520/kafka,rhauch/kafka,mihbor/kafka