sysdeps: docbook-xsl is docbook-style-xsl in Fedora

Update 'gtk-doc' and 'libnotify' modules to use
the more precise name dep so the user is reported
the correct package name to install.

Issue #65
2 jobs for docbook5_fedora in 10 minutes and 34 seconds
latest
Status Job ID Name Coverage
  Test
passed test-py3 #1190712

00:02:09

passed ub20.04-py3-glib #1190713

00:10:34