Fix example AGSL code in the javadoc comments

Need to land this fix in tm-dev for it to show up in the published reference docs.

Bug: 237562620
Test: [go/atsd docs build]
Change-Id: I5f562b70d04bc86779190002a2640fb51dc00531
(cherry picked from commit 0547bffe40)

graphics/java/android/graphics/RuntimeShader.java

@@ -214,7 +214,7 @@ import libcore.util.NativeAllocationRegistry;
  * uniform shader myShader;
  * vec4 main(vec2 canvas_coordinates) {
  *     // swap the red and blue color channels when sampling from myShader
- *     return myShader.sample(canvas_coordinates).bgra;
+ *     return myShader.eval(canvas_coordinates).bgra;
  * }</pre>
  *
  * <p>After creating a {@link RuntimeShader} with that program the shader uniform can