fix old field name

`rasterization_state` is an old field name of
`wgpu::RenderPipelineDescriptor`

docs/beginner/tutorial4-buffer/README.md

@@ -32,7 +32,7 @@ const VERTICES: &[Vertex] = &[
 ];
 ```
 
-We arrange the vertices in counter-clockwise order: top, bottom left, bottom right. We do it this way partially out of tradition, but mostly because we specified in the `rasterization_state` of the `render_pipeline` that we want the `front_face` of our triangle to be `wgpu::FrontFace::Ccw` so that we cull the back face. This means that any triangle that should be facing us should have its vertices in counter-clockwise order.
+We arrange the vertices in counter-clockwise order: top, bottom left, bottom right. We do it this way partially out of tradition, but mostly because we specified in the `primitive` of the `render_pipeline` that we want the `front_face` of our triangle to be `wgpu::FrontFace::Ccw` so that we cull the back face. This means that any triangle that should be facing us should have its vertices in counter-clockwise order.
 
 Now that we have our vertex data, we need to store it in a buffer. Let's add a `vertex_buffer` field to `State`.