window: Add shortcut for adding collections

cartridges/ui/shortcuts-dialog.blp

@@ -49,4 +49,13 @@ Adw.ShortcutsDialog shortcuts_dialog {
       accelerator: "Delete";
     }
   }
+
+  Adw.ShortcutsSection {
+    title: _("Collections");
+
+    Adw.ShortcutsItem {
+      title: _("Add Collection");
+      accelerator: "<Control><Shift>n";
+    }
+  }
 }

cartridges/ui/window.blp

@@ -21,6 +21,12 @@ template $Window: Adw.ApplicationWindow {
       action: "action(win.add)";
     }
 
+    Shortcut {
+      trigger: "<Control><Shift>n";
+      action: "action(win.add-collection)";
+      arguments: "''";
+    }
+
     Shortcut {
       trigger: "<Control>z";
       action: "action(win.undo)";