[gobject-introspection] Add missing nullable annotation to g_irepository_get_shared_library

[Christoph Reiter <creiter src gnome org>]

commit 487d3f01bcd4c2bc9adbe2d4aaa77b2c37c44795
Author: Jonne Haß <me jhass eu>
Date:   Thu May 14 15:20:25 2020 +0000

    Add missing nullable annotation to g_irepository_get_shared_library

 girepository/girepository.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/girepository/girepository.c b/girepository/girepository.c
index b7948d61..7d034859 100644
--- a/girepository/girepository.c
+++ b/girepository/girepository.c
@@ -1144,7 +1144,7 @@ g_irepository_get_version (GIRepository *repository,
  * Note: The namespace must have already been loaded using a function
  * such as g_irepository_require() before calling this function.
  *
- * Returns: Comma-separated list of paths to shared libraries,
+ * Returns: (nullable): Comma-separated list of paths to shared libraries,
  *   or %NULL if none are associated
  */
 const gchar *