docs, Gnome-module: document include_directories in gtkdoc
This parameter is supported for some time but has never been documented.
@@ -323,6 +323,7 @@ of the module.
* `dependencies`: a list of dependencies
* `fixxref_args`: a list of arguments to pass to `gtkdoc-fixxref`
* `gobject_typesfile`: a list of type files
+* `include_directories`: extra include paths to pass to `gtkdoc-scangobj`
* `ignore_headers`: a list of header files to ignore
* `html_assets`: a list of assets for the HTML pages
* `html_args` a list of arguments to pass to `gtkdoc-mkhtml`
