[css-color-5][editorial] Update changes

Author: svgeesus

css-color-5/Overview.bs

@@ -3667,7 +3667,10 @@ This specification adds a way to ensure adequate contrast for text whose backgro
 </h3>
 
 <ul>
-	<!-- to 3 June 2025 -->
+	<!-- to 320 August 2025 -->
+	<li>Added display-p3-linear to color spaces for interpolation</li>
+	<li>Added the alpha() RCS function</li>
+	<li>Updated explanatory prose which still limited color-mix to two colors</li>
 	<li>Clarified fetching external URLs for style resources</li>
 	<li>Clarified that sole item in color-mix() is returned in the specified color space</li>
 	<li>Made color mixing algorithm pass the normalization flag</li>