[glib] Better documentation for g_app_info_equal()

[Matthias Clasen <matthiasc src gnome org>]

commit 85882094df02ab6d3f8773e9dda2b96d89b59ad1
Author: Adrian Perez de Castro <aperez igalia com>
Date:   Tue Jan 31 03:10:24 2017 +0200

    Better documentation for g_app_info_equal()
    
    Explicitly state that the function may not compare the contents of the
    passed GAppInfo instances.
    
    This fixes bug #777961.

 gio/gappinfo.c |    4 ++++
 1 files changed, 4 insertions(+), 0 deletions(-)
---
diff --git a/gio/gappinfo.c b/gio/gappinfo.c
index 30501fd..4c8c288 100644
--- a/gio/gappinfo.c
+++ b/gio/gappinfo.c
@@ -139,6 +139,10 @@ g_app_info_dup (GAppInfo *appinfo)
  *
  * Checks if two #GAppInfos are equal.
  *
+ * Note that the check <em>may not</em> compare each individual field, and
+ * only does an identity check. In case detecting changes in the contents
+ * is needed, program code must additionally compare relevant fields.
+ *
  * Returns: %TRUE if @appinfo1 is equal to @appinfo2. %FALSE otherwise.
  **/
 gboolean