Revert C# 8 assignment in NewsFeedElement.cs

Author: thedillonb

CodeHub.iOS/DialogElements/NewsFeedElement.cs

@@ -88,7 +88,7 @@ public NewsFeedElement(string imageUrl, DateTimeOffset time, IEnumerable<TextBlo
                 if (b.Tapped != null)
                     color = LinkColor;
 
-                color ??= primaryColor;
+                color = color ?? primaryColor;
 
                 var str = new NSAttributedString(b.Value, new CoreText.CTStringAttributes() { ForegroundColor = color.CGColor, Font = ctFont });
                 attributedString.Append(str);