Bug#1118763: debian-policy: Don't mention doc-base any more

[Jeremy Bícha <jbicha@debian.org>]

For comparison, GNOME has long had an app named Devhelp for reading
API documentation with a sidebar allowing easy access to any installed
docs that have registered themselves with a .devhelp2 file. GNOME has
recently archived the Devhelp app in favor of a new app named Manuals
which still supports the .devhelp2 files. (This app is currently in
Debian's NEW queue.)

I count about 366 .devhelp2 files on my system. It is heavily weighted
towards library used by app or system developers for GTK desktops
(GNOME, Xfce, etc.).

There are a few packages that provide the older .devhelp or
.devhelp.gz format but Manuals does not support that format.

I count about 4757 files in /usr/share/doc-base/

The devhelp app has a popcon of 1426 installs, larger than all the
doc-base clients combined. The gnome-builder app has a popcon of 680
and gnome-builder has integrated devhelp2 support similar to the
Manuals app.

The .devhelp2 files are part of the upstream projects. I don't think
anyone is writing those files downstream specifically for Debian.

I'm not really suggesting now that devhelp be mentioned in Debian
Policy, but this is just a contrast with an alternate way of solving
this problem.

Thank you,
Jeremy Bícha