fix doc link

Author: mbostock

CHANGELOG.md

@@ -47,7 +47,7 @@ Plot.plot({
 })
 ```
 
-The [barycentric interpolator](https://observablehq.com/plot/marks/raster#interpolatorbarycentric-options) used by the [raster](https://observablehq.com/plot/marks/raster) and [contour](https://observablehq.com/plot/marks/contour) marks now behaves correctly outside the convex hull of samples. The new algorithm (below right) radiates outwards from the hull, ensuring a continuous image; the old algorithm (below left) radiated inwards from values imputed on the frame’s edges, producing discontinuities.
+The [barycentric interpolator](https://observablehq.com/plot/marks/raster#interpolatorBarycentric) used by the [raster](https://observablehq.com/plot/marks/raster) and [contour](https://observablehq.com/plot/marks/contour) marks now behaves correctly outside the convex hull of samples. The new algorithm (below right) radiates outwards from the hull, ensuring a continuous image; the old algorithm (below left) radiated inwards from values imputed on the frame’s edges, producing discontinuities.
 
 <img src="./img/barycentric-before-after.png" width="640" alt="A before-and-after comparison of the barycentric interpolator applied to three sample points; in the new algorithm, lines radiate outward perpendicular from the triangle’s sides, producing a more coherent and understandable image.">