xdg-config: fix typos and wording and use ReST format

Signed-off-by: Nicolas Iooss <nicolas.iooss_git@polytechnique.org>
XDG: create xdgconfig directory with a python program which apply a well-known saved dconf configuration

Signed-off-by: Nicolas Iooss <nicolas.iooss_git@polytechnique.org>
shell/aliases: add openssl and getfattr aliases

Signed-off-by: Nicolas Iooss <nicolas.iooss_git@polytechnique.org>