Merge branch 'th/ghash-steal-extended-doc' into 'main'

ghash: document g_hash_table_steal_extended() behavior for sets

See merge request GNOME/glib!2948

glib/ghash.c

@@ -1839,6 +1839,10 @@ g_hash_table_steal (GHashTable    *hash_table,
  * You can pass %NULL for @lookup_key, provided the hash and equal functions
  * of @hash_table are %NULL-safe.
  *
+ * The dictionary implementation optimizes for having all values identical to
+ * their keys, for example by using g_hash_table_add(). When stealing both the
+ * key and the value from such a dictionary, the value will be %NULL.
+ *
  * Returns: %TRUE if the key was found in the #GHashTable
  * Since: 2.58
  */