add accessibility outline properties to the custom properties overview

Author: haschek

src/configuration/stories/customproperties.stories.tsx

@@ -34,6 +34,10 @@ const groups: { title: string; filterName: (name: string) => boolean }[] = [
         title: "Color aliases",
         filterName: (name) => name.startsWith(`--${eccgui}-color`) && !name.startsWith(`--${eccgui}-color-palette`),
     },
+    {
+        title: "Accessibility",
+        filterName: (name) => name.startsWith(`--${eccgui}-a11y`),
+    },
     {
         title: "Opacity",
         filterName: (name) => name.startsWith(`--${eccgui}-opacity`),