Add documentation to avoid/fix HF_HUB_DISABLE_SYMLINKS_WARNING for windows users

[bmerkle]

Describe the bug

When downloading models on windows I get the warning below because of missing symlinks in Windows.
I can deactivate the warning via HF_HUB_DISABLE_SYMLINKS_WARNING which works but it is better to save diskspace and use symlink. For windows this requires one of 2 config steps which we should document in the readme.

we have 3 options:

1. Enable Developer Mode on Windows (one-time setup) https://learn.microsoft.com/en-us/windows/advanced-settings/developer-mode
2. Run Python as administrator when using Olive
3. Keep using HF_HUB_DISABLE_SYMLINKS_WARNING=1 to suppress the warning and accept the extra disk usage

I would vote that we include these options into the docs with a hint for windows users (as the problem only occurs there)

regarding the options, the user should decide what is possible in his environment (e.g. company policies) and which option fits best for him (albeit option 3 does not fix the problem at all)

Reproduction

simply download a model on windows

Logs

C:\work\microsoft\Olive\venv\Lib\site-packages\huggingface_hub\file_download.py:143: UserWarning: `huggingface_hub` cache-system uses symlinks by default to efficiently store duplicated files but your machine does not support them in C:\Users\merklbe1\.cache\huggingface\hub\models--Qwen--Qwen2.5-Coder-0.5B-Instruct. Caching files will still work but in a degraded version that might require more space on your disk. This warning can be disabled by setting the `HF_HUB_DISABLE_SYMLINKS_WARNING` environment variable. For more details, see https://huggingface.co/docs/huggingface_hub/how-to-cache#limitations.
To support symlinks on Windows, you either need to activate Developer Mode or to run Python as an administrator. In order to activate developer mode, see this article: https://docs.microsoft.com/en-us/windows/apps/get-started/enable-your-device-for-development
  warnings.warn(message)

System info

- huggingface_hub version: 0.36.0
- Platform: Windows-11-10.0.26100-SP0
- Python version: 3.12.5
- Running in iPython ?: No
- Running in notebook ?: No
- Running in Google Colab ?: No
- Running in Google Colab Enterprise ?: No
- Token path ?: C:\Users\merklbe1\.cache\huggingface\token
- Has saved token ?: True
- Who am I ?: bmerkle
- Configured git credential helpers: manager
- FastAI: N/A
- Tensorflow: N/A
- Torch: 2.9.1
- Jinja2: 3.1.6
- Graphviz: N/A
- keras: N/A
- Pydot: N/A
- Pillow: N/A
- hf_transfer: N/A
- gradio: N/A
- tensorboard: N/A
- numpy: 2.3.5
- pydantic: 2.12.5
- aiohttp: N/A
- hf_xet: 1.2.0
- ENDPOINT: https://huggingface.co
- HF_HUB_CACHE: C:\Users\merklbe1\.cache\huggingface\hub
- HF_ASSETS_CACHE: C:\Users\merklbe1\.cache\huggingface\assets
- HF_TOKEN_PATH: C:\Users\merklbe1\.cache\huggingface\token
- HF_STORED_TOKENS_PATH: C:\Users\merklbe1\.cache\huggingface\stored_tokens
- HF_HUB_OFFLINE: False
- HF_HUB_DISABLE_TELEMETRY: False
- HF_HUB_DISABLE_PROGRESS_BARS: None
- HF_HUB_DISABLE_SYMLINKS_WARNING: False
- HF_HUB_DISABLE_EXPERIMENTAL_WARNING: False
- HF_HUB_DISABLE_IMPLICIT_TOKEN: False
- HF_HUB_DISABLE_XET: False
- HF_HUB_ENABLE_HF_TRANSFER: False
- HF_HUB_ETAG_TIMEOUT: 10
- HF_HUB_DOWNLOAD_TIMEOUT: 10

[Wauplin]

Hi @bmerkle, I do think this symlink issue is already correctly documented at the moment. As you've mentioned, the warning log already tells the user that they run on a degraded version, that they can fix that, or at least disable the warning if they can't run dev/admin mode, and moreover provides links to the docs (https://huggingface.co/docs/huggingface_hub/v1.2.3/guides/manage-cache#limitations) for more details. I don't think adding more documentation to the README makes sense (it scatters the information without adding more details).