chore: build with Go 1.26; use Go 1.25 features (#10570)

WaitGroup.Go and built-in gomaxprocs handling.

Signed-off-by: Jakob Borg <jakob@kastelo.net>

cmd/syncthing/main.go

@@ -42,7 +42,6 @@ import (
 	"github.com/syncthing/syncthing/internal/db"
 	"github.com/syncthing/syncthing/internal/db/sqlite"
 	"github.com/syncthing/syncthing/internal/slogutil"
-	_ "github.com/syncthing/syncthing/lib/automaxprocs"
 	"github.com/syncthing/syncthing/lib/build"
 	"github.com/syncthing/syncthing/lib/config"
 	"github.com/syncthing/syncthing/lib/dialer"

cmd/syncthing/monitor.go

@@ -137,17 +137,8 @@ func (c *serveCmd) monitorMain() {
 
 		var wg sync.WaitGroup
 
-		wg.Add(1)
-		go func() {
-			copyStderr(stderr, dst)
-			wg.Done()
-		}()
-
-		wg.Add(1)
-		go func() {
-			copyStdout(stdout, dst)
-			wg.Done()
-		}()
+		wg.Go(func() { copyStderr(stderr, dst) })
+		wg.Go(func() { copyStdout(stdout, dst) })
 
 		exit := make(chan error)