Improve CSS comment

web_demo/index.html

@@ -37,12 +37,7 @@
             width: 100%;
         }
 
-        /* Position canvas in center-top.
-        This is rather arbitrarily chosen.
-        In particular, it seems like both Chromium and Firefox will still align
-        the canvas on the physical pixel grid, which is required to get
-        pixel-perfect (non-blurry) rendering in egui.
-        See https://github.com/emilk/egui/issues/4241 for more */
+        /* Make canvas fill entire document: */
         canvas {
             margin-right: auto;
             margin-left: auto;