Update sessions.xml

Author: PPPDUD

security/sessions.xml

@@ -4,8 +4,8 @@
   <title>Session Security</title>
 
   <para>
-   It is important keeping HTTP session management secure. Session
-   related security is described in
+   It is important to keep your HTTP session management secure. Session
+   related security is described in the
    <link linkend="session.security">Session Security</link> section
    of <link linkend="book.session">Session module</link> reference.
   </para>