Revert "docs: Improve CONTRIBUTING.md (#303)"

This reverts commit d14daa6.

Author: ValerianRey

CONTRIBUTING.md

@@ -47,10 +47,7 @@ with maintainers before implementing major changes.
     pdm run pytest tests/unit tests/doc --cov=src
     ```
 
-## Building the documentation
-
-### Locally
-
+## Building the documentation locally
    - From the `docs` folder, run:
      ```bash
      pdm run make html
@@ -62,13 +59,6 @@ with maintainers before implementing major changes.
      pdm run make clean
      ```
 
-### Online
-
-- When you open a pull request, a GitHub action should build and deploy the documentation, which
-  will become available at `torchjd.org/pr/<pr_number>`. Additionally, you can click on the check
-  status of the action, then click on `Summary`, and then click on the link of the built
-  documentation.
-
 ## Development guidelines
 
 The following guidelines should help preserve a good code quality in TorchJD. Contributions that do