[gnome-calendar] project: Fix the build with -Denable-gtk-doc=true

[Georges Basile Stavracas Neto <gbsneto src gnome org>]

commit c232aaff69fe29f9abd5b3de65993ae6c1c06fd2
Author: Kalev Lember <klember redhat com>
Date:   Wed Sep 13 23:06:35 2017 +0200

    project: Fix the build with -Denable-gtk-doc=true
    
    https://bugzilla.gnome.org/show_bug.cgi?id=787653

 doc/reference/meson.build |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/doc/reference/meson.build b/doc/reference/meson.build
index 3d9faeb..fee048c 100644
--- a/doc/reference/meson.build
+++ b/doc/reference/meson.build
@@ -37,7 +37,7 @@ gnome.gtkdoc(
   gobject_typesfile: meson.project_name() + '.types',
         html_assets: html_images,
             install: true,
-        install_dir: doc_path
+        install_dir: doc_path,
        fixxref_args: [
     '--extra-dir=@0@'.format(join_paths(gtk_doc_path, 'evolution-data-server')),
     '--extra-dir=@0@'.format(join_paths(glib_doc_path, 'glib')),