Add follow-up comment with guess why it must be 96

Change-Id: Ifa725c40c5756ba7999423a782180c1ac3901d30

vcl/quartz/salgdicommon.cxx

@@ -1407,6 +1407,11 @@ void AquaSalGraphics::GetResolution( sal_Int32& rDPIX, sal_Int32& rDPIY )
     // don't match each others at their boundaries, and other issues). But *why* it must be 96 I
     // have no idea. The commit that changed it to 96 from (the arbitrary) 200 did not say. If you
     // know where else 96 is explicitly or implicitly hard-coded, please modify this comment.
+
+    // Follow-up: It might be this: in 'online', loleaflet/src/map/Map.js:
+        // 15 = 1440 twips-per-inch / 96 dpi.
+        // Chosen to match previous hardcoded value of 3840 for
+        // the current tile pixel size of 256.
     rDPIX = rDPIY = 96;
 #endif
 }