Switch library documentation to gi-docgen

Switch from gtk-doc to gi-docgen for the library documentation and
adjust the source files accordingly.

We don't bother about the daemon doc headers as they're not built into
any docs atm.

Closes: #56

debian/control

@@ -5,9 +5,10 @@ Maintainer: Guido Günther <agx@sigxcpu.org>
 Build-Depends:
  dbus,
  debhelper-compat (= 12),
+ docbook-xsl <!nodoc>,
  dh-sequence-gir,
  gsettings-desktop-schemas <!nocheck>,
- gtk-doc-tools,
+ gi-docgen <!nodoc>,
  json-glib-tools,
  libgirepository1.0-dev,
  libglib2.0-dev,
@@ -17,6 +18,7 @@ Build-Depends:
  meson,
  pkg-config,
  valac,
+ xsltproc <!nodoc>,
 Standards-Version: 4.4.0
 Homepage: https://source.puri.sm/Librem5/feedbackd
 

debian/libfeedback-dev.install

@@ -1,6 +1,6 @@
 /usr/include
 /usr/share/gir-1.0/
-/usr/share/gtk-doc/
+/usr/share/doc/libfeedback-0 /usr/share/doc/libfeedback-dev/
 /usr/share/vala/
 /usr/lib/*/libfeedback-*.so
 /usr/lib/*/pkgconfig/libfeedback-*.pc

debian/libfeedback-dev.links

@@ -0,0 +1 @@
+usr/share/doc/libfeedback-dev/libfeedback-0 usr/share/devhelp/books/libfeedback-0