net/netns: fix controlLogf doc

Its doc said its signature matched a std signature, but it used
Tailscale-specific types.

Nowadays it's the caller (func control) that curries the logf/netmon
and returns the std-matching signature.

Updates #cleanup (while answering a question on Slack)

Change-Id: Ic99de41fc6a1c720575a7f33c564d0bcfd9a2c30
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>

net/netns/netns_darwin.go

@@ -33,10 +33,8 @@ var bindToInterfaceByRouteEnv = envknob.RegisterBool("TS_BIND_TO_INTERFACE_BY_RO
 
 var errInterfaceStateInvalid = errors.New("interface state invalid")
 
-// controlLogf marks c as necessary to dial in a separate network namespace.
-//
-// It's intentionally the same signature as net.Dialer.Control
-// and net.ListenConfig.Control.
+// controlLogf binds c to a particular interface as necessary to dial the
+// provided (network, address).
 func controlLogf(logf logger.Logf, netMon *netmon.Monitor, network, address string, c syscall.RawConn) error {
 	if isLocalhost(address) {
 		// Don't bind to an interface for localhost connections.