Update html-page-lang-matches-default-ucwvc8.md

Author: giacomo-petri

_rules/html-page-lang-matches-default-ucwvc8.md

@@ -41,7 +41,10 @@ This rule applies to any [document element][] if it is an `html` element for whi
 - The [document element][] is in a [top-level browsing context][]; and
 - The [document element][] has a [content type][] of `text/html`; and
 - The [document element][] has a defined [default page language][]; and
-- The [document element][] has at least one [descendant](https://dom.spec.whatwg.org/#concept-tree-descendant) [text node][] which is neither empty nor only [whitespace][].
+- The [document element][] has at least one of the following [descendant](https://dom.spec.whatwg.org/#concept-tree-descendant) that is not empty or only [whitespace][]:
+	- [text node][] that is included in the accessibility tree; or
+ 	- an element's [accessible name][] or [accessible description](https://www.w3.org/TR/accname-1.1/#dfn-accessible-description) that is exposed in the accessibility tree; or
+  	- the document's title.
 
 ## Expectation