docs: document how to write documentation
As a template the Syncthing documentation on how to document has been used: https://github.com/syncthing/docs/blob/341fed46bd4e40f3a7a10cd649aac43c13d24e21/README.rst
As a template the Syncthing documentation on how to document has been used: https://github.com/syncthing/docs/blob/341fed46bd4e40f3a7a10cd649aac43c13d24e21/README.rst