Cleanup comments.

src/pdf/XPDFRenderer.cpp

@@ -301,7 +301,7 @@ QImage& XPDFRenderer::createPDFImageCached(int pageNumber, TypePdfZoomCacheData
         {
             if(cacheData.splash != nullptr)
             {
-                cacheData.cachedImage = QImage(); // The 'm_pdfZoomCachedImage' uses a buffer from 'mSplash'.
+                cacheData.cachedImage = QImage();
                 delete cacheData.splash;
             }
             cacheData.splash = new SplashOutputDev(splashModeRGB8, 1, false, paperColor);

src/pdf/XPDFRenderer.h

@@ -100,8 +100,6 @@ class XPDFRenderer : public PDFRenderer
 
         PDFDoc *mDocument;
         static QAtomicInt sInstancesCount;
-        //! The image is rendered with a quality above normal, so we can use that same
-        //! image while zooming.
         qreal mSliceX;
         qreal mSliceY;
 };