[goffice] Introspection: nullable fixes.

[Morten Welinder <mortenw src gnome org>]

commit 19e97070513c9da6a1a2dd20da59ba187547d8d3
Author: Morten Welinder <terra gnome org>
Date:   Fri Mar 30 14:42:15 2018 -0400

    Introspection: nullable fixes.
    
    Still to verify: does the oldest version we support actually accept
    "nullable"?

 NEWS               |    3 +++
 goffice/app/file.c |   10 +++++-----
 2 files changed, 8 insertions(+), 5 deletions(-)
---
diff --git a/NEWS b/NEWS
index 9645298..5dd6c47 100644
--- a/NEWS
+++ b/NEWS
@@ -1,5 +1,8 @@
 goffice 0.10.40:
 
+Hiroshi Hatake:
+       * Introspction fixes. [#793684]
+
 Morten:
        * Fixes required for running with musl.  [#794115]
        * Store last-know modtime for GODoc.
diff --git a/goffice/app/file.c b/goffice/app/file.c
index ea24aae..08f0ccc 100644
--- a/goffice/app/file.c
+++ b/goffice/app/file.c
@@ -247,7 +247,7 @@ go_file_opener_setup (GOFileOpener *fo, gchar const *id,
 
 /**
  * go_file_opener_new:
- * @id: Optional ID of the opener (or NULL)
+ * @id: (nullable): Optional ID of the opener
  * @description: Description of supported file format
  * @suffixes: (element-type char): List of suffixes to associate with the opener
  * @mimes: (element-type char): List of mime types to associate with the opener
@@ -278,7 +278,7 @@ go_file_opener_new (gchar const *id,
 
 /**
  * go_file_opener_new_with_enc:
- * @id: Optional ID of the opener (or NULL)
+ * @id: (nullable): Optional ID of the opener
  * @description: Description of supported file format
  * @suffixes: (element-type char): List of suffixes to associate with the opener
  * @mimes: (element-type char): List of mime types to associate with the opener
@@ -395,7 +395,7 @@ go_file_opener_probe (GOFileOpener const *fo, GsfInput *input, GOFileProbeLevel
 /**
  * go_file_opener_open:
  * @fo: GOFileOpener object
- * @opt_enc: Optional encoding
+ * @opt_enc: (nullable): Optional encoding
  * @io_context: Context for i/o operation
  * @view: #GoView
  * @input: Gsf input stream
@@ -690,8 +690,8 @@ GSF_CLASS (GOFileSaver, go_file_saver,
 
 /**
  * go_file_saver_new:
- * @id: Optional ID of the saver (or NULL)
- * @extension: Optional default extension of saved files (or NULL)
+ * @id: (nullable): Optional ID of the saver
+ * @extension: (nullable): Optional default extension of saved files
  * @description: Description of supported file format
  * @level: File format level
  * @save_func: (scope async): Pointer to "save" function