Contribute documentation improvements

Thank you for improving our documentation! Every addition made is read thousands of times and has a tremendous impact.

These are the sources for the ITK docs sphinx website.

The contribution process generally follows our contributing guidelines.

Once merged into master, the documentation will be available in the latest version of the ReadTheDocs documentation as https://docs.itk.org/. Note that latest is not the default version (release is). To change versions, use the links in the lower left of the page.

To preview documentation changes, three options are available.

Option 0: Edit on GitHub, use the pull request preview

If files are edited with GitHub’s web user interface, the pull request will build a preview of changes with a pull request check called docs/readthedocs.org:itk. Click on the Details link to view the documentation build preview.

Option 1: Build and serve locally

To compile the document locally create a python virtual environment and install the required packages.

For example in Linux / macOS:

cd ITK/Documentation/docs
python -m venv env
source env/bin/activate
pip install -r requirements.txt

Use make html in this directory to build the documentation. Open _build/html/index.html in your browser to inspect the result.

Option 2: Autobuild and serve locally

To automatically rebuild the website with any input markdown changes and serve the result, use sphinx-autobuild

cd ITK/Documentation/docs
pip install -r requirements.txt
pip install sphinx-autobuild

sphinx-autobuild -a . _build/html

This will start a server at http://127.0.0.1:8000 and rebuild whenever the documentation changes.