Remove the outdated comment

While containerd/cgroups is only for Linux, the metrics subcommand works
on Windows.

Signed-off-by: Kazuyoshi Kato <katokazu@amazon.com>

cmd/ctr/commands/tasks/metrics.go

@@ -32,12 +32,6 @@ import (
 	"github.com/urfave/cli"
 )
 
-func init() {
-	// metricsCommand is only added on Linux as github.com/containerd/cgroups/v3
-	// does not compile on darwin or windows
-	Command.Subcommands = append(Command.Subcommands, metricsCommand)
-}
-
 const (
 	formatFlag  = "format"
 	formatTable = "table"

cmd/ctr/commands/tasks/tasks.go

@@ -38,6 +38,7 @@ var Command = cli.Command{
 		execCommand,
 		listCommand,
 		killCommand,
+		metricsCommand,
 		pauseCommand,
 		psCommand,
 		resumeCommand,