[css-fonts-4] Fix ID for the font-variant-emoji section

Author: xfq

css-fonts-4/Overview.bs

@@ -3633,7 +3633,7 @@ might result in different used palettes
 because the value of variables inside the ''@font-palette-values'' rule
 might apply differently in the context of those two elements.
 
-<h3 id="font-variant-emoji-desc">
+<h3 id="font-variant-emoji-prop">
 Selecting the text presentation style: The 'font-variant-emoji' property</h3>
 
 <pre class="propdef">