Updated wording

doc/en/webgl/README.md

@@ -2,7 +2,7 @@
 
 In this module, we'll use WebGL to do custom rendering of meteorite impact data from a CSV file.
 
-The module starts out rendering points with a normal vector layer using the Canvas 2D context.  Then we'll use new point rendering utilities to render the same data with WebGL.  Finally, we'll develop a custom fragment shader to show how the data can be dynamically styled.
+The module starts out rendering points with a normal vector layer using the Canvas 2D context.  Then we'll use new point rendering utilities to render the same data with WebGL.  Finally, we'll use custom style expressions to show how the data can be dynamically styled.
 
 * [Setup](meteorites.md)
 * [Rendering points](points.md)