GitLab

* Fix has_file in offline mode

* harmonize env variable for offline mode

* Switch to HF_HUB_OFFLINE

* fix test

* revert test_offline to test TRANSFORMERS_OFFLINE

* Add new offline test

* merge conflicts

* docs

* Script & Manual edition

* Update

Switch to the conda-forge channel for transformer installation,
as the huggingface channel does not offer the latest version.

Fixes #28248

* Rename index.mdx to index.md

* With saved modifs

* Address review comment

* Treat all files

* .mdx -> .md

* Remove special char

* Update utils/tests_fetcher.py
Co-authored-by: Lysandre Debut <lysandre.debut@reseau.eseo.fr>

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Co-authored-by: Lysandre Debut <lysandre.debut@reseau.eseo.fr>

* Add the Italian translation of the file installation.mdx and edit _toctree

* Add the Italian translation of the file installation.mdx and edit _toctree