Log Message:
gtk-doc: update to 1.27.

GTK-Doc 1.27  (Dec 07 2017)
==============

Finetune the python port.

 Changes

 o 773879 : scangobj: Do not generate unused parameters
 o 786174 : Several test failures on Arch Linux
 o 787495 : gtkdoc-fixxref crashes when running vim for syntax highlighting
 o 787768 : Aborts when glib2.0-dev is not installed
 o 787862 : Always open files in text mode and always use utf-8
 o 788473 : fixxref crashes if a .devhelp2.gz file is found
 o 789531 : Don't depend on the system shell
 o 790022 : mkdb: Add support for (not optional) annotation
 o 791131 : gtk-doc and python3: fixxref failures