Doc: Mark a few things as private

docs/reference/gio/gio-sections.txt

@@ -4257,6 +4257,11 @@ g_task_get_type
 <FILE>gnetworking</FILE>
 <TITLE>gnetworking.h</TITLE>
 g_networking_init
+<SUBSECTION Private>
+CMSG_LEN
+CMSG_SPACE
+GLIB_ALIGN_TO_SIZEOF
+T_SRV
 </SECTION>
 
 <SECTION>

gio/gresource.c

@@ -186,7 +186,7 @@ g_resource_unref (GResource *resource)
     }
 }
 
-/**
+/*< internal >
  * g_resource_new_from_table:
  * @table: (transfer full): a GvdbTable
  *

gio/gresource.h

@@ -51,6 +51,7 @@ GQuark g_resource_error_quark (void);
 typedef struct _GStaticResource GStaticResource;
 
 struct _GStaticResource {
+  /*< private >*/
   const guint8 *data;
   gsize data_len;
   GResource *resource;

gio/gsettingsbackend.h

@@ -110,6 +110,7 @@ struct _GSettingsBackendClass
                                      const gchar         *key,
                                      const GVariantType  *expected_type);
 
+  /*< private >*/
   gpointer padding[23];
 };