treat \ as escape only before a separator

mapper_linux_test.go

@@ -0,0 +1,26 @@
+//go:build !windows
+// +build !windows
+
+package kong_test
+
+import (
+	"os"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestPathMapper(t *testing.T) {
+	var cli struct {
+		Path string `arg:"" type:"path"`
+	}
+	p := mustNew(t, &cli)
+
+	_, err := p.Parse([]string{"/an/absolute/path"})
+	require.NoError(t, err)
+	require.Equal(t, "/an/absolute/path", cli.Path)
+
+	_, err = p.Parse([]string{"-"})
+	require.NoError(t, err)
+	require.Equal(t, "-", cli.Path)
+}