[doc]Modify quantization tutorials (#5026)

### What this PR does / why we need it?
Modify quantization tutorials to correct a few mistakes:
Qwen3-32B-W4A4.md and Qwen3-8B-W4A8.md
Qwen3-8B-W4A8: need to set one idle npu card.
Qwen3-32B-W4A4: need to set two idle npu cards for the flatquant
training and modify the calib_file path which does not match the
ModeSlim version.
### Does this PR introduce _any_ user-facing change?
N/A
### How was this patch tested?

- vLLM version: v0.12.0
- vLLM main:
vllm-project/vllm@ad32e3e

Signed-off-by: IncSec <[email protected]>

Author: InSec

docs/source/tutorials/Qwen3-32B-W4A4.md

@@ -55,10 +55,12 @@ cd example/Qwen
 MODEL_PATH=/home/models/Qwen3-32B
 # Path to save converted weight, Replace with your local path
 SAVE_PATH=/home/models/Qwen3-32B-w4a4
+# Set two idle NPU cards
+export ASCEND_RT_VISIBLE_DEVICES=0,1
 
 python3 w4a4.py --model_path $MODEL_PATH \
                 --save_directory $SAVE_PATH \
-                --calib_file ../common/qwen_qwen3_cot_w4a4.json \
+                --calib_file ./calib_data/qwen3_cot_w4a4.json \
                 --trust_remote_code True \
                 --batch_size 1
 ```

docs/source/tutorials/Qwen3-8B-W4A8.md

@@ -47,6 +47,8 @@ cd example/Qwen
 MODEL_PATH=/home/models/Qwen3-8B
 # Path to save converted weight, Replace with your local path
 SAVE_PATH=/home/models/Qwen3-8B-w4a8
+# Set an idle NPU card
+export ASCEND_RT_VISIBLE_DEVICES=0
 
 python quant_qwen.py \
           --model_path $MODEL_PATH \