Update fonts.mdx

Author: mintlify[bot]

fonts.mdx

@@ -142,7 +142,7 @@ You can also use external font URLs instead of local files:
           Font weight for headings.
         </ResponseField>
         <ResponseField name="source" type="string (uri)">
-          Path to your local font file or external URL for headings.
+          URL to your font source, such as `https://mintlify-assets.b-cdn.net/fonts/Hubot-Sans.woff2` or path to your local font file for headings. [Google Fonts](https://fonts.google.com) are loaded automatically when you specify a Google Font `family` name, so no source URL is needed.
         </ResponseField>
         <ResponseField name="format" type="'woff' | 'woff2'">
           Font file format for headings.