[docs] Add missing parenthesis in the sample code of BLIP Diffusion (huggingface#5144)

Add missing parenthesis in the sample code of BLIP Diffusion

Author: hysts

src/diffusers/pipelines/controlnet/pipeline_controlnet_blip_diffusion.py

@@ -51,7 +51,7 @@
 
         >>> cldm_cond_image = load_image(
         ...     "https://huggingface.co/datasets/ayushtues/blipdiffusion_images/resolve/main/kettle.jpg"
-        ... ).resize(512, 512)
+        ... ).resize((512, 512))
         >>> canny = CannyDetector()
         >>> cldm_cond_image = canny(cldm_cond_image, 30, 70, output_type="pil")
         >>> style_image = load_image(