Update introduction.html
Fixing small grammar issue with plural versions
Reviewers: Mickael Maison
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- In Kafka the communication between the clients and the servers is done with a simple, high-performance, language agnostic <a href="https://kafka.apache.org/protocol.html">TCP protocol</a>. This protocol is versioned and maintains backwards compatibility with older version. We provide a Java client for Kafka, but clients are available in <a href="https://cwiki.apache.org/confluence/display/KAFKA/Clients">many languages</a>.</p>
+ In Kafka the communication between the clients and the servers is done with a simple, high-performance, language agnostic <a href="https://kafka.apache.org/protocol.html">TCP protocol</a>. This protocol is versioned and maintains backwards compatibility with older versions. We provide a Java client for Kafka, but clients are available in <a href="https://cwiki.apache.org/confluence/display/KAFKA/Clients">many languages</a>.</p>
<h4><a id="intro_topics" href="#intro_topics">Topics and Logs</a></h4>
<p>Let's first dive into the core abstraction Kafka provides for a stream of records&mdash;the topic.</p>
