Ensure that the HTML emitted for members is correct.

This was using the `symbol` property, which will use the type of the member’s related type. Instead, it should use the member being iterated over.

Author: samsymons

Sources/swift-doc/Supporting Types/Components/Members.swift

@@ -93,7 +93,7 @@ struct Members: Component {
                     <h2>\#(section.title)</h2>
             
                     \#(section.members.map { member -> HypertextLiteral.HTML in
-                        let descriptor = String(describing: type(of: symbol.api)).lowercased()
+                        let descriptor = String(describing: type(of: member.api)).lowercased()
 
                         return #"""
                         <div role="article" class="\#(descriptor)" id=\#(member.id.description.lowercased().replacingOccurrences(of: " ", with: "-"))>