docs: Document more accessible roles

GtkListView and GtkGridView were missing this as well.

gtk/gtkgridview.c

@@ -77,6 +77,11 @@
  * GtkGridView uses a single CSS node with name gridview. Each child
  * uses a single CSS node with name child. For rubberband selection,
  * a subnode with name rubberband is used.
+ *
+ * # Accessibility
+ *
+ * GtkGridView uses the #GTK_ACCESSIBLE_ROLE_GRID role, and the items
+ * use the #GTK_ACCESSIBLE_ROLE_GRID_CELL role.
  */
 
 typedef struct _Cell Cell;

gtk/gtklistview.c

@@ -135,6 +135,11 @@
  * The main listview node may also carry style classes to select
  * the style of [list presentation](ListContainers.html#list-styles):
  * .rich-list, .navigation-sidebar or .data-table.
+ *
+ * # Accessibility
+ *
+ * GtkListView uses the #GTK_ACCESSIBLE_ROLE_LIST role, and the list
+ * items use the #GTK_ACCESSIBLE_ROLE_LIST_ITEM role.
  */
 
 typedef struct _ListRow ListRow;