Apply suggestions from code review

Author: yiyixuxu

src/diffusers/pipelines/wan/pipeline_wan.py

@@ -52,15 +52,9 @@
         >>> # Available models: Wan-AI/Wan2.1-T2V-14B-Diffusers, Wan-AI/Wan2.1-T2V-1.3B-Diffusers
         >>> model_id = "Wan-AI/Wan2.1-T2V-14B-Diffusers"
         >>> vae = AutoencoderKLWan.from_pretrained(model_id, subfolder="vae", torch_dtype=torch.float32)
-        >>> flow_shift = 5.0  # 5.0 for 720P, 3.0 for 480P
-        >>> scheduler = UniPCMultistepScheduler(
-        ...     prediction_type="flow_prediction",
-        ...     use_flow_sigmas=True,
-        ...     num_train_timesteps=1000,
-        ...     flow_shift=flow_shift,
-        ... )
         >>> pipe = WanPipeline.from_pretrained(model_id, vae=vae, torch_dtype=torch.bfloat16)
-        >>> pipe.scheduler = scheduler
+        >>> flow_shift = 5.0  # 5.0 for 720P, 3.0 for 480P
+        >>> pipe.scheduler = UniPCMultistepScheduler.from_config(pipe.scheduler.config, flow_shift=flow_shift)
         >>> pipe.to("cuda")
 
         >>> prompt = "A cat and a dog baking a cake together in a kitchen. The cat is carefully measuring flour, while the dog is stirring the batter with a wooden spoon. The kitchen is cozy, with sunlight streaming through the window."