Use Qt 5's QStringList::join(QChar)

Less typing and less cycles than join(QString) where appropriate

Change-Id: I6ebc0e17e4d7fd9845864dd95b7de4ba4dad6906
Reviewed-by: Eike Ziller <eike.ziller@digia.com>

src/libs/qmljs/qmljslink.cpp

@@ -431,7 +431,7 @@ Import LinkPrivate::importNonFile(Document::Ptr doc, const ImportInfo &importInf
                   "%1\n\n"
                   "For qmake projects, use the QML_IMPORT_PATH variable to add import paths.\n"
                   "For qmlproject projects, use the importPaths property to add import paths.").arg(
-                  importPaths.join(QLatin1String("\n"))));
+                  importPaths.join(QLatin1Char('\n'))));
     }
 
     return import;