message: Update readme example
diff: @@ -29,7 +29,7 @@ pub fn create_instance(&self,
  create_info: &vk::InstanceCreateInfo,
  allocation_callbacks: Option<&vk::AllocationCallbacks>)
  -> Result<Instance, InstanceError> {
  -let instance: Instance = entry.create_instance(&create_info, None)
  +let instance = entry.create_instance(&create_info, None)
  .expect("Instance creation error");
  ```
  