[examples] Fix CLI argument in the launch script command for text2image with LoRA (#2171)

* Update README.md

* Update README.md

examples/text_to_image/README.md

@@ -148,7 +148,7 @@ huggingface-cli login
 Now we can start training!
 
 ```bash
-accelerate --mixed_precision="fp16" launch train_text_to_image_lora.py \
+accelerate launch --mixed_precision="fp16" train_text_to_image_lora.py \
   --pretrained_model_name_or_path=$MODEL_NAME \
   --dataset_name=$DATASET_NAME --caption_column="text" \
   --resolution=512 --random_flip \
@@ -157,7 +157,7 @@ accelerate --mixed_precision="fp16" launch train_text_to_image_lora.py \
   --learning_rate=1e-04 --lr_scheduler="constant" --lr_warmup_steps=0 \
   --seed=42 \
   --output_dir="sd-pokemon-model-lora" \
-  --save_sample_prompt="cute dragon creature" --report_to="wandb"
+  --validation_prompt="cute dragon creature" --report_to="wandb"
 ```
 
 The above command will also run inference as fine-tuning progresses and log the results to Weights and Biases.