Make user strings translatable

Go-ahead given by Albert on kde-i18n-doc@kde.org - sorry for making
things difficult.

src/lib/file.cpp

@@ -177,7 +177,7 @@ bool browseFile(QString& file, const QString& caption, QString& defaultDir,
     QStringList nameFilters;
     if (!fileNameFilter.isEmpty())
         nameFilters << fileNameFilter;
-    nameFilters << QStringLiteral("All files (*)");
+    nameFilters << QStringLiteral("%1 (*)").arg(i18nc("@item:inlistbox File type", "All files"));
     fileDlg->setNameFilters(nameFilters);
     if (!initialFile.isEmpty())
         fileDlg->selectFile(initialFile);

src/soundpicker.cpp

@@ -311,7 +311,7 @@ bool SoundPicker::browseFile(QString& file, QString& defaultDir, const QString&
     static QString audioFilter;
     if (audioFilter.isEmpty())
     {
-        audioFilter = QStringLiteral("Audio files (");
+        audioFilter = QStringLiteral("%1 (").arg(i18nc("@item:inlistbox", "Audio files"));
         QMimeDatabase db;
         const QStringList mimeTypes = Phonon::BackendCapabilities::availableMimeTypes();
         for (const QString& mimeType : mimeTypes)