* In the doc, the explicit and outdated list of required
dependencies is removed. Now, launching `./admin/build-doc`
is suggested because the script gives the missing dependencies.
* Little refactoring of the "Debian checking dependencies" part
in the script `./admin/build-doc`.
* In the suggested "apt-get" command to install dependencies, the
option `-o APT::Install-Recommends=true` is added just in case.
Signed-off-by: François Lafont <francois.lafont@ac-versailles.fr>
