multi-choice: Bind category to tooltip + a11y label

This adds a tooltip to the multi choice buttons, with the text
"Previous/Next (category)". This fixes the warnings in the date
chooser popover.

Part-of: <https://gitlab.gnome.org/GNOME/gnome-calendar/-/merge_requests/681>

src/gui/event-editor/gcal-multi-choice.blp

@@ -3,11 +3,13 @@ using Gtk 4.0;
 template $GcalMultiChoice: Box {
   spacing: 6;
   accessible-role: spin_button;
+  notify::category => $set_accessibility_label() swapped;
 
   Button down_button {
     icon-name: "pan-start-symbolic";
     clicked => $button_clicked_cb();
     can-focus: false;
+    tooltip-text: bind $get_down_button_tooltip(template.category) as <string>;
 
     styles [
       "back-button",
@@ -53,6 +55,7 @@ template $GcalMultiChoice: Box {
     icon-name: "pan-end-symbolic";
     clicked => $button_clicked_cb();
     can-focus: false;
+    tooltip-text: bind $get_up_button_tooltip(template.category) as <string>;
 
     styles [
       "circular",

src/gui/event-editor/gcal-multi-choice.c

@@ -24,6 +24,8 @@
 
 #include "gcal-multi-choice.h"
 
+#include <glib/gi18n.h>
+
 struct _GcalMultiChoice
 {
   GtkBox                          parent;
@@ -159,6 +161,26 @@ set_value (GcalMultiChoice         *self,
   g_object_notify_by_pspec (G_OBJECT (self), properties[PROP_VALUE]);
 }
 
+static gchar *
+get_down_button_tooltip (GcalMultiChoice    *self,
+                         gchar              *category)
+{
+  g_autofree gchar *formatted_tooltip = NULL;
+
+  formatted_tooltip =  g_strdup_printf (_("Previous %1$s"), category);
+  return g_steal_pointer (&formatted_tooltip);
+}
+
+static gchar *
+get_up_button_tooltip (GcalMultiChoice    *self,
+                         gchar              *category)
+{
+  g_autofree gchar *formatted_tooltip = NULL;
+
+  formatted_tooltip =  g_strdup_printf (_("Next %1$s"), category);
+  return g_steal_pointer (&formatted_tooltip);
+}
+
 static void
 go_up (GcalMultiChoice *self)
 {
@@ -224,6 +246,14 @@ update_sensitivity (GcalMultiChoice *self)
                                    GTK_ACCESSIBLE_RELATION_CONTROLS);
 }
 
+static void
+set_accessibility_label (GcalMultiChoice *self)
+{
+  gtk_accessible_update_property (GTK_ACCESSIBLE (self),
+                                  GTK_ACCESSIBLE_PROPERTY_LABEL,
+                                  gcal_multi_choice_get_category (self), -1);
+}
+
 static void
 button_clicked_cb (GtkWidget       *button,
                    GcalMultiChoice *self)
@@ -672,10 +702,13 @@ gcal_multi_choice_class_init (GcalMultiChoiceClass *class)
   gtk_widget_class_bind_template_child (widget_class, GcalMultiChoice, label1);
   gtk_widget_class_bind_template_child (widget_class, GcalMultiChoice, label2);
 
+  gtk_widget_class_bind_template_callback (widget_class, set_accessibility_label);
   gtk_widget_class_bind_template_callback (widget_class, button_clicked_cb);
   gtk_widget_class_bind_template_callback (widget_class, button_toggled_cb);
   gtk_widget_class_bind_template_callback (widget_class, button_state_flags_changed_cb);
   gtk_widget_class_bind_template_callback (widget_class, key_pressed_cb);
+  gtk_widget_class_bind_template_callback (widget_class, get_down_button_tooltip);
+  gtk_widget_class_bind_template_callback (widget_class, get_up_button_tooltip);
 
   gtk_widget_class_set_css_name (widget_class, "navigator");
 }