First Steps: add missing l10n string

Sources/VLCFirstStepsFifthPageViewController.m

@@ -28,7 +28,7 @@
     self.subtitlesLabel.text = NSLocalizedString(@"FIRST_STEPS_SUBTITLES", @"");
     self.audioLabel.text = NSLocalizedString(@"FIRST_STEPS_AUDIO", @"");
     self.volumeLabel.text = NSLocalizedString(@"FIRST_STEPS_VOLUME", @"");
-    self.positionLabel.text = NSLocalizedString(@"BUTTON_POSITION", @"");
+    self.positionLabel.text = NSLocalizedString(@"FIRST_STEPS_POSITION", @"");
 }
 
 - (void)viewWillAppear:(BOOL)animated