doc: use trtllm-llmapi-launch for multi-node Triton (#772)

Signed-off-by: Aurelien Chartier <2567591+achartier@users.noreply.github.com>

Author: achartier

docs/llmapi.md

@@ -102,7 +102,7 @@ srun -N 2 \
  --mpi=pmix \
  --container-image=<your image> \
  --container-mounts=$(pwd)/tensorrt_llm/:/code \
- bash /code/triton_backend/scripts/triton_task.sh
+ trtllm-llmapi-launch /opt/tritonserver/bin/tritonserver --model-repository llmapi_repo
 
 ```