[gnome-online-accounts/gnome-3-38] client: Mention that goa_client_get_manager might return NULL

[Debarshi Ray <debarshir src gnome org>]

commit 8240fd109c21fd2005d213a07c20298c4f836b82
Author: Debarshi Ray <debarshir gnome org>
Date:   Fri Oct 9 16:48:35 2020 +0200

    client: Mention that goa_client_get_manager might return NULL
    
    If the org.gnome.OnlineAccounts D-Bus service isn't available, then
    goa_client_get_manager might return NULL.
    
    https://gitlab.gnome.org/GNOME/gnome-online-accounts/-/issues/139

 src/goa/goaclient.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/src/goa/goaclient.c b/src/goa/goaclient.c
index afec7104..19f2bd66 100644
--- a/src/goa/goaclient.c
+++ b/src/goa/goaclient.c
@@ -403,9 +403,9 @@ goa_client_get_object_manager (GoaClient        *self)
  * goa_client_get_manager:
  * @self: A #GoaClient.
  *
- * Gets the #GoaManager for @self.
+ * Gets the #GoaManager for @self, if any.
  *
- * Returns: (transfer none): A #GoaManager. Do not free, the returned
+ * Returns: (transfer none): A #GoaManager or %NULL. Do not free, the returned
  * object belongs to @self.
  */
 GoaManager *