[css-text-decor-4] Adjustments to l4 for spelling and grammar errors

Author: frivoal

css-text-decor-4/Overview.bs

@@ -228,6 +228,10 @@ Text Underline Offset: the 'text-underline-offset' property</h3>
 			<span class="issue">Should this be removed?</span>
 	</ul>
 
+	When the value of the 'text-decoration-line' property is either
+	''spelling-error'' or ''grammar-error'',
+	the UA may ignore the value of 'text-underline-position'.
+
 <h3 id="text-decoration-skip-property">
 Text Decoration Line Continuity: the 'text-decoration-skip' property</h3>
 
@@ -337,6 +341,10 @@ Text Decoration Line Continuity: the 'text-decoration-skip' property</h3>
 		ins, del { text-decoration-skip: none; }
 	</code></pre>
 
+	When the value of the 'text-decoration-line' property is either
+	''spelling-error'' or ''grammar-error'',
+	the UA may ignore the value of 'text-decoration-skip'.
+
 <h2 id=temp>Rescued L3 Brainstorming: Ignore For Now</h2>
 
 <h3 id="text-emphasis-skip">