Fix typos and plurals

src/securityvalidationmodel.cpp

@@ -22,7 +22,7 @@
 #include <QtAlgorithms>
 
 const QString SecurityValidationModel::messages[static_cast<const int>(SecurityFlaw::COUNT)] = {
-   QObject::tr("Your communication negotation is secured, but not the media stream, please enable ZRTP or SDES"),
+   QObject::tr("Your communication negotiation is secured, but not the media stream, please enable ZRTP or SDES"),
    QObject::tr("TLS is disabled, the negotiation wont be encrypted. Your communication will be vulnerable to "
    "snooping"),
    QObject::tr("Your certificate is expired, please contact your system administrator."),