Fix comment typos in OutputDevice::DrawTransparent()

Change-Id: I52e9d505719b3f3b985cd5300ebacb5caa57873f
Reviewed-on: https://gerrit.libreoffice.org/8777Reviewed-by: Chris Sherlock <chris.sherlock79@gmail.com>
Tested-by: Chris Sherlock <chris.sherlock79@gmail.com>

vcl/source/gdi/outdev6.cxx

@@ -294,7 +294,7 @@ void OutputDevice::DrawTransparent( const PolyPolygon& rPolyPoly,
             && GetBitCount() > 8
 #endif
 #ifdef WIN32
-        // workaround bad dithering on remote displaying when using GDI+ with toolbar buttoin hilighting
+        // workaround bad dithering on remote displaying when using GDI+ with toolbar button highlighting
         && !rPolyPoly.IsRect()
 #endif
         )