Fix linter errors (except for tests)

internal/backend/mem/mem_backend.go

@@ -28,7 +28,7 @@ func NewFactory() location.Factory {
 
 	return location.NewHTTPBackendFactory[struct{}, *MemoryBackend](
 		"mem",
-		func(s string) (*struct{}, error) {
+		func(_ string) (*struct{}, error) {
 			return &struct{}{}, nil
 		},
 		location.NoPassword,

internal/backend/rclone/backend.go

@@ -183,7 +183,7 @@ func newBackend(ctx context.Context, cfg Config, lim limiter.Limiter) (*Backend,
 	dialCount := 0
 	tr := &http2.Transport{
 		AllowHTTP: true, // this is not really HTTP, just stdin/stdout
-		DialTLS: func(network, address string, cfg *tls.Config) (net.Conn, error) {
+		DialTLS: func(network, address string, _ *tls.Config) (net.Conn, error) {
 			debug.Log("new connection requested, %v %v", network, address)
 			if dialCount > 0 {
 				// the connection to the child process is already closed