fix invalid usage tag & [https://issues.apache.org/jira/browse/NLPCRAFT-175]

Signed-off-by: Sree Vaddi <441385+sreev@users.noreply.github.com>
diff --git a/src/main/java/org/apache/nlpcraft/client/NCClient.java b/src/main/java/org/apache/nlpcraft/client/NCClient.java
index 79c7432..ed25952 100644
--- a/src/main/java/org/apache/nlpcraft/client/NCClient.java
+++ b/src/main/java/org/apache/nlpcraft/client/NCClient.java
@@ -49,7 +49,7 @@
  *     // Perform any necessary calls...
  *     NCResult res = cli.askSync("my.model.id", txt);
  *
- *     // Close client & sign out at the end.
+ *     // Close client &amp; sign out at the end.
  *     cli.close();
  * </pre>
  * 
diff --git a/src/main/java/org/apache/nlpcraft/client/NCClientBuilder.java b/src/main/java/org/apache/nlpcraft/client/NCClientBuilder.java
index b004425..c0a238b 100644
--- a/src/main/java/org/apache/nlpcraft/client/NCClientBuilder.java
+++ b/src/main/java/org/apache/nlpcraft/client/NCClientBuilder.java
@@ -40,7 +40,7 @@
  *     // Perform any necessary calls...
  *     NCResult res = cli.askSync("my.model.id", txt);
  *
- *     // Close client & sign out at the end.
+ *     // Close client &amp; sign out at the end.
  *     cli.close();
  * </pre>
  */