Fix typo.

README.md

@@ -632,7 +632,7 @@ Produces a cubic [basis spline](https://en.wikipedia.org/wiki/B-spline) using th
 
 <img src="https://raw.githubusercontent.com/d3/d3-shape/master/img/bundle.png" width="888" height="240" alt="bundle">
 
-Produces a straighted cubic [basis spline](https://en.wikipedia.org/wiki/B-spline) using the specified control points, with the spline straightened according to the specified parameter *beta* in the range [0, 1]. If *beta* equals zero, a straight line between the first and last point is produced; if *beta* equals one, a standard [basis](#basis) spline is produced. If *beta* is not specified, it defaults to 0.85. This curve is typically used in [hierarchical edge bundling](http://bl.ocks.org/mbostock/7607999) to disambiguate connections, as proposed by [Danny Holten](https://www.win.tue.nl/vis1/home/dholten/) in [Hierarchical Edge Bundles: Visualization of Adjacency Relations in Hierarchical Data](https://www.win.tue.nl/vis1/home/dholten/papers/bundles_infovis.pdf); *beta* represents the bundle strength.
+Produces a straightened cubic [basis spline](https://en.wikipedia.org/wiki/B-spline) using the specified control points, with the spline straightened according to the specified parameter *beta* in the range [0, 1]. If *beta* equals zero, a straight line between the first and last point is produced; if *beta* equals one, a standard [basis](#basis) spline is produced. If *beta* is not specified, it defaults to 0.85. This curve is typically used in [hierarchical edge bundling](http://bl.ocks.org/mbostock/7607999) to disambiguate connections, as proposed by [Danny Holten](https://www.win.tue.nl/vis1/home/dholten/) in [Hierarchical Edge Bundles: Visualization of Adjacency Relations in Hierarchical Data](https://www.win.tue.nl/vis1/home/dholten/papers/bundles_infovis.pdf); *beta* represents the bundle strength.
 
 <a name="cardinal" href="#cardinal">#</a> d3_shape.<b>cardinal</b>(<i>context</i>[, <i>tension</i>])