[docs] Update interface in repaint.mdx (#3119)

Update repaint.mdx

accomodate to #1701

Author: ernestchu

docs/source/en/api/pipelines/repaint.mdx

@@ -60,7 +60,7 @@ pipe = pipe.to("cuda")
 
 generator = torch.Generator(device="cuda").manual_seed(0)
 output = pipe(
-    original_image=original_image,
+    image=original_image,
     mask_image=mask_image,
     num_inference_steps=250,
     eta=0.0,