Use QStringList::join(QChar) overload where applicable [QtGui]

This is an automated change performing the following replacements:
                    join\("(.)"\) -> join('\1')
  join\(QLatin1String\("(.)"\)\)  -> join(QLatin1Char('\1'))
  join\(QStringLiteral\("(.)"\)\) -> join(QLatin1Char('\1'))

Change-Id: Id8d43c1b1ca9cd3aa0b4eedca6709b6287a9bc98
Reviewed-by: Gunnar Sletta <gunnar.sletta@nokia.com>

src/gui/accessible/qaccessible.cpp

@@ -1190,7 +1190,7 @@ Q_GUI_EXPORT QDebug operator<<(QDebug d, const QAccessibleInterface *iface)
             stateStrings << QLatin1String("invisible");
 
         if (!stateStrings.isEmpty())
-            d << stateStrings.join(QLatin1String("|"));
+            d << stateStrings.join(QLatin1Char('|'));
 
         if (!st.invisible)
             d << "rect=" << iface->rect();

src/platformsupport/input/evdevkeyboard/qevdevkeyboardmanager.cpp

@@ -69,7 +69,7 @@ QEvdevKeyboardManager::QEvdevKeyboardManager(const QString &key, const QString &
     }
 
     // build new specification without /dev/ elements
-    m_spec = args.join(QLatin1String(":"));
+    m_spec = args.join(QLatin1Char(':'));
 
     // add all keyboards for devices specified in the argument list
     foreach (const QString &device, devices)

src/platformsupport/input/evdevmouse/qevdevmousemanager.cpp

@@ -75,7 +75,7 @@ QEvdevMouseManager::QEvdevMouseManager(const QString &key, const QString &specif
     }
 
     // build new specification without /dev/ elements
-    m_spec = args.join(QLatin1String(":"));
+    m_spec = args.join(QLatin1Char(':'));
 
     // add all mice for devices specified in the argument list
     foreach (const QString &device, devices)