Fix incorrect statement in the pointsize documentation

doc/_tutorial/properties.ipynb

@@ -742,7 +742,7 @@
     "\n",
     "The `pointsize` property is relevant to dot marks and to line marks that can show markers at individual data points. The units correspond to the diameter of the mark in points.\n",
     "\n",
-    "The `pointsize` scales with the square root of the data by default so that magnitude is represented by diameter rather than area:"
+    "Note that, while the parameterization corresponds to diameter, scales will be applied with a square root transform so that data values are linearly proportional to area:"
    ]
   },
   {