update CHANGELOG

Author: mbostock

CHANGELOG.md

@@ -75,7 +75,7 @@ With the new *symmetric* option, the apparent difference between −3% and 0 is
 
 <img width="641" alt="a choropleth with symmetric diverging scale, showing the change in population of the fifty U.S. states between 2010 and 2019; the change in negative values is commensurate with the change in positive values" src="https://user-images.githubusercontent.com/230541/129834634-2617a895-5040-4135-b015-0aa4b812c262.png">
 
-Diverging color scales now also support transformations via four new scale types: *diverging-sqrt*, *diverging-pow*, *diverging-log*, and *diverging-symlog*, corresponding to the *sqrt*, *pow*, *log*, and *symlog* quantitative scale types respectively.
+Diverging color scales now also support transformations via four new scale types: *diverging-sqrt*, *diverging-pow*, *diverging-log*, and *diverging-symlog*, corresponding to the *sqrt*, *pow*, *log*, and *symlog* quantitative scale types respectively. (The above choropleth uses a *diverging-log* scale to show relative change.)
 
 The new axis *line* option, which defaults to false, can be used to show a continuous line along the *x* or *y* axis. Using a rule to annotate a meaningful value, such as zero, is generally preferred over the *line* option.
 
@@ -130,9 +130,9 @@ When the facet *data* is null, a better error message is thrown.
 
 ### Transforms
 
-The bin and group transforms now support *filter*, *sort* and *reverse* options on the *outputs* object. By setting the *filter* to null, the bin transform will now return empty bins; this is useful with marks such as lines and areas that require zeroes to be present, rather than interpolating across the missing bins. (The *z*, *fill* or *stroke* channels, when used for grouping, are propagated to empty bins.) The *outputs* argument to the bin and group transforms is now optional; it defaults to the *count* reducer for *y*, *x* and *fill* for Plot.binX, Plot.binY, and Plot.bin respectively, and the same for the group transforms.
+The bin and group transforms now support new *filter*, *sort* and *reverse* options on the *outputs* object. By setting the *filter* to null, the bin transform will now return empty bins; this is useful with marks such as lines and areas that require zeroes to be present, rather than interpolating across the missing bins. (The *z*, *fill* or *stroke* channels, when used for grouping, are propagated to empty bins.) The *outputs* argument to the bin and group transforms is now optional; it defaults to the *count* reducer for *y*, *x* and *fill* for Plot.binX, Plot.binY, and Plot.bin respectively, and the same for the group transforms.
 
-The bin and group transforms now support the *distinct*, *mode*, *min-index*, and *max-index* reducers. The *distinct* reducer counts the number of distinct values in each group, while the *mode* reducer returns the most frequent value in each group. The *min-index* and *max-index* reducers are similar to *min* and *max*, except they return the zero-based index of the minimum and maximum value, respectively; for example, this is useful to sort time series by the date of each series’ peak.
+The bin and group transforms now support new *distinct*, *mode*, *min-index*, and *max-index* reducers. The *distinct* reducer counts the number of distinct values in each group, while the *mode* reducer returns the most frequent value in each group. The *min-index* and *max-index* reducers are similar to *min* and *max*, except they return the zero-based index of the minimum and maximum value, respectively; for example, this is useful to sort time series by the date of each series’ peak.
 
 The default *thresholds* option for the bin transforms is now *auto* instead of *scott*, while applies a maximum limit of 200 bins to Scott’s rule. This avoids vanishing rects when they are too numerous and thin to be visible. (Note, however, that it is still possible to produce invisible rects if the insets are larger than the width.)