wf: correct IPv6 link-local range from ff80::/10 to fe80::/10 (tailscale#17840)

Fixes tailscale#17833

Signed-off-by: Sachin Iyer <siyer@detail.dev>

Author: sachiniyer

wf/firewall.go

@@ -18,7 +18,7 @@ import (
 
 // Known addresses.
 var (
-	linkLocalRange           = netip.MustParsePrefix("ff80::/10")
+	linkLocalRange           = netip.MustParsePrefix("fe80::/10")
 	linkLocalDHCPMulticast   = netip.MustParseAddr("ff02::1:2")
 	siteLocalDHCPMulticast   = netip.MustParseAddr("ff05::1:3")
 	linkLocalRouterMulticast = netip.MustParseAddr("ff02::2")