docs: add --no-deps to ROCm install in training.md

[fuergaosi233]

Summary

ROCm install in docs/basic_usage/training.md used a bare pip install -e . after requirements-rocm.txt. pyproject.toml pins CUDA-default torch==2.13.0 and sglang==0.5.18, so that full resolve can overwrite a working ROCm stack.

docs/get_started/installation.md and docs/basic_usage/AMD/amd_rocm.md already require --no-deps. This matches them.

Local repro

# stale command in training.md
python -m pip install -r requirements-rocm.txt
python -m pip install -e .
# pip can re-resolve pyproject and pull CUDA torch/sglang

# required command (installation.md / amd_rocm.md)
python -m pip install -e . --no-deps

On main (2fc9930), training.md L460 is python -m pip install -e . with no --no-deps.

Test plan

• Diff is training.md only
• ROCm block now uses python -m pip install -e . --no-deps
• CUDA/Ascend instructions unchanged