Update CHANGELOG

Author: mbostock

CHANGELOG.md

@@ -28,7 +28,7 @@ The mark [sort options](./README.md#sort-options) now support implicit “width
 Plot.rectY(energy, {x: "Year", interval: 1, y: "Value", fill: "Description", sort: {color: "height"}})
 ```
 
-The [bin transform](./README.md#bin) now supports *x* and *y* reducers which represent the midpoint of the bin: (*x1* + *x2*) / 2 and (*y1* + *y2*) / 2 respectively. The [bin](./README.md#bin), [group](./README.md#group), and [window](./README.md#window) transforms now support percentile reducers of the form *pXX* where *XX* is a number in [00, 99]. For example *p25* represents the first quartile and *p75* represents the third quartile.
+The [bin transform](./README.md#bin) now supports *x* and *y* reducers which represent the midpoint of the bin: (*x1* + *x2*) / 2 and (*y1* + *y2*) / 2 respectively. The [bin](./README.md#bin), [group](./README.md#group), and [window](./README.md#window) transforms now support percentile reducers of the form *pXX* where *XX* is a number in [00, 99]; for example *p25* represents the first quartile and *p75* represents the third quartile.
 
 The error message when attempting to create a standalone legend without a valid scale definition has been improved. The high cardinality warning for the implicit *z* channel has been relaxed; it is now only triggered if more than half of the values are distinct. When the axis *ticks* option is specified as null, no ticks are generated. When the axis *tickFormat* option is specified as null, no tick labels are generated.