[gtksourceview] map: add ".GtkSourceMap" class to overview map

[Christian Hergert <chergert src gnome org>]

commit a4662690d4b3767f75537fb792167f7c30978881
Author: Christian Hergert <chergert redhat com>
Date:   Thu Oct 14 17:47:06 2021 -0700

    map: add ".GtkSourceMap" class to overview map
    
    This is just a convenience thing since we are already a "textview".

 gtksourceview/gtksourcemap.c | 2 ++
 1 file changed, 2 insertions(+)
---
diff --git a/gtksourceview/gtksourcemap.c b/gtksourceview/gtksourcemap.c
index 7aaa217e..2f1fdcc8 100644
--- a/gtksourceview/gtksourcemap.c
+++ b/gtksourceview/gtksourcemap.c
@@ -1244,6 +1244,8 @@ gtk_source_map_init (GtkSourceMap *map)
 
        priv = gtk_source_map_get_instance_private (map);
 
+       gtk_widget_add_css_class (GTK_WIDGET (map), "GtkSourceMap");
+
        priv->css_provider = gtk_css_provider_new ();
         priv->slider = g_object_new (GTK_SOURCE_TYPE_MAP_SLIDER,
                                     "width-request", 1,