[libadwaita/wip/cdavis/stylesheet-selection-doc: 781/781] doc: Mention that selection mode does nothing

[Christopher Davis <christopherdavis src gnome org>]

commit 48394b8bb74cbc3861e685537de7cb068f35d4fc
Author: Christopher Davis <christopherdavis gnome org>
Date:   Thu Oct 14 10:17:24 2021 -0700

    doc: Mention that selection mode does nothing

 doc/migrating-libhandy-1-4-to-libadwaita.md | 6 ++++++
 1 file changed, 6 insertions(+)
---
diff --git a/doc/migrating-libhandy-1-4-to-libadwaita.md b/doc/migrating-libhandy-1-4-to-libadwaita.md
index 9e491cdf..83943432 100644
--- a/doc/migrating-libhandy-1-4-to-libadwaita.md
+++ b/doc/migrating-libhandy-1-4-to-libadwaita.md
@@ -458,6 +458,12 @@ style.
 The same rules are also used for the [`.toolbar`](style-classes.html#toolbars)
 style class now, instead of making every button appear flat.
 
+The `.selection-mode` style class no longer recolors headerbars. Instead
+of using the old styling, rework your selection modes to follow
+[the new pattern for selection 
modes](https://developer.gnome.org/hig/patterns/containers/selection-mode.html)
+and the [`.selection-mode`](style-classes.html#selection-mode-check-buttons)
+style class on [class@Gtk.CheckButton].
+
 #### Adapt to List Style Changes
 
 For boxed lists we now have the