MINOR: Fix invalid link to plugin.path property docs in quickstart (#12523)
MINOR: Fix invalid link to plugin.path property docs in quickstart (#12523)

Reviewers: Chris Egerton <f27d60f3e5e364231bb9280e41fe11da6ae20fb5@gmail.com>
guozhangwang/kafka,apache/kafka,apache/kafka,guozhangwang/kafka,apache/kafka,guozhangwang/kafka,guozhangwang/kafka,apache/kafka