Flax/Jax documentation (#8331)

* First addition of Flax/Jax documentation

Signed-off-by: Morgan Funtowicz <morgan@huggingface.co>

* make style

* Ensure input order match between Bert & Roberta

Signed-off-by: Morgan Funtowicz <morgan@huggingface.co>

* Install dependencies "all" when building doc

Signed-off-by: Morgan Funtowicz <morgan@huggingface.co>

* wraps build_doc deps with ""

Signed-off-by: Morgan Funtowicz <morgan@huggingface.co>

* Addressing @sgugger comments.

Signed-off-by: Morgan Funtowicz <morgan@huggingface.co>

* Use list to highlight JAX features.

Signed-off-by: Morgan Funtowicz <morgan@huggingface.co>

* Make style.

Signed-off-by: Morgan Funtowicz <morgan@huggingface.co>

* Let's not look to much into the future for now.

Signed-off-by: Morgan Funtowicz <morgan@huggingface.co>

* Style

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

.circleci/config.yml

@@ -281,7 +281,7 @@ jobs:
                       - v0.4-build_doc-{{ checksum "setup.py" }}
                       - v0.4-{{ checksum "setup.py" }}
             - run: pip install --upgrade pip
-            - run: pip install .[tf,torch,sentencepiece,docs]
+            - run: pip install ."[all, docs]"
             - save_cache:
                   key: v0.4-build_doc-{{ checksum "setup.py" }}
                   paths: