[Doc] CLI Args Naming Style Correction (#1750)

Signed-off-by: Didan Deng <33117903+wtomin@users.noreply.github.com>

docs/features/custom_pipeline.md

@@ -115,7 +115,7 @@ python image_edit.py \
     --image cherry_blossom.jpg \
     --prompt "Let this mascot dance under the moon, surrounded by floating stars" \
     --output output_image_edit.png \
-    --num_inference_steps 10
+    --num-inference-steps 10
 ```
 
 ## Advanced Usage