Use QStringList directly for setting.

For installed documentation. Instead of splitting a string at ';'.

Change-Id: I0e0ad0ece337bc8738501c008ff67412df1f18bb
Reviewed-by: Alexander Lenhardt <alexander.lenhardt@nokia.com>

src/plugins/coreplugin/helpmanager.cpp

@@ -439,7 +439,7 @@ QStringList HelpManagerPrivate::documentationFromInstaller()
 {
     QSettings *installSettings = Core::ICore::instance()->settings();
     QStringList documentationPaths = installSettings->value(QLatin1String("Help/InstalledDocumentation"))
-            .toString().split(QLatin1Char(';'), QString::SkipEmptyParts);
+            .toStringList();
     QStringList documentationFiles;
     foreach (const QString &path, documentationPaths) {
         QFileInfo pathInfo(path);