LibCore: Support IPv6 for TCP and UDP connection

Author: https://github.com/xlmnxp 🔰
Commit: ab82fc8993
Pull-request: https://github.com/LadybirdBrowser/ladybird/pull/276
Reviewed-by: https://github.com/ADKaster ✅
Reviewed-by: https://github.com/Hendiadyoin1
Reviewed-by: https://github.com/circl-lastname

AK/Forward.h

@@ -35,6 +35,7 @@ class Error;
 class FlyString;
 class GenericLexer;
 class IPv4Address;
+class IPv6Address;
 class JsonArray;
 class JsonObject;
 class JsonValue;
@@ -167,6 +168,7 @@ using AK::GenericLexer;
 using AK::HashMap;
 using AK::HashTable;
 using AK::IPv4Address;
+using AK::IPv6Address;
 using AK::JsonArray;
 using AK::JsonObject;
 using AK::JsonValue;