[docs] add starlight overrides map link (#2417)

Co-authored-by: Chris Swithinbank <[email protected]>

docs/src/content/docs/guides/overriding-components.mdx

@@ -24,6 +24,10 @@ Overriding Starlight’s default components can be useful when:
 1. Choose the Starlight component you want to override.
    You can find a full list of components in the [Overrides Reference](/reference/overrides/).
 
+	 :::tip
+	 Not sure which component you need to override? Use the [interactive Starlight Overrides Map](https://starlight-overrides-map.netlify.app/) to discover the names of Starlight's UI components.
+	 :::
+
    This example will override Starlight’s [`SocialIcons`](/reference/overrides/#socialicons) component in the page nav bar.
 
 2. Create an Astro component to replace the Starlight component with.