Rename the EntityRenderer#getRenderState method to createRenderState

[haykam821]

The EntityRenderer#getRenderState method is only used to initialize a field:

private final S state = this.getRenderState();

It also returns a new EntityRenderState instance each time, as can be seen in the EmptyEntityRenderer#getRenderState method as well as other implementations:

@Override
public EntityRenderState getRenderState() {
	return new EntityRenderState();
}

As such, createRenderState would be a more fitting name.