os/signal: use slices.Delete

Change-Id: I212a0f4f97e1c938f56981f278464081cfd75e85
Reviewed-on: https://go-review.googlesource.com/c/go/+/613875
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Michael Pratt <mpratt@google.com>
Auto-Submit: Tobias Klauser <tobias.klauser@gmail.com>
Reviewed-by: Ian Lance Taylor <iant@google.com>

src/os/signal/signal.go

@@ -7,6 +7,7 @@ package signal
 import (
 	"context"
 	"os"
+	"slices"
 	"sync"
 )
 
@@ -217,7 +218,7 @@ func Stop(c chan<- os.Signal) {
 
 	for i, s := range handlers.stopping {
 		if s.c == c {
-			handlers.stopping = append(handlers.stopping[:i], handlers.stopping[i+1:]...)
+			handlers.stopping = slices.Delete(handlers.stopping, i, i+1)
 			break
 		}
 	}