Build documentation

Documentation is based on :

• |restructuredtext|_ files in :file:`./docs/manual` and :file:`docs/developers/`

  ??

• HTML templates

• python sources

• image files

All these inputs files have to be checked : typo free, expected results, ...

cf. coding rules ++ lint

|sphinx| is used to produce HTML and PDF files.

.. todo::
   These files are shipped with distribution ++.

cd ${PROJECT}/docs/manual/
make clean
make html
make linkcheck

Check if no broken links are identified by this last command.

Check the HTML result by opening a browser on the main entry file:

xdg-open _build/html/index.html &

Check by opening the PDF file

xdg-open _build/latex/igcmg_doc.pdf &

.. todo:: decide URI, authorized people, etc.
   cf. :ref:`installdoc`