docs: update with new ignore option

Author: danielroe

docs/content/0.index.md

@@ -86,6 +86,8 @@ npx nuxi@latest module add html-validator
     usePrettier: false,
     logLevel: 'verbose',
     failOnError: false,
+    /** A list of routes to ignore (that is, not check validity for). */
+    ignore: [/\.(xml|rss|json)$/],
     options: {
       extends: [
         'html-validate:document',