fix #2190 - don't use backslash for "embed" paths on windows

codegen/data.go

@@ -3,7 +3,7 @@ package codegen
 import (
 	"fmt"
 	"os"
-	"path/filepath"
+	"path"
 	"sort"
 	"strings"
 
@@ -177,8 +177,8 @@ func BuildData(cfg *config.Config) (*Data, error) {
 			return nil, fmt.Errorf("failed to get working directory: %w", err)
 		}
 		outputDir := cfg.Exec.Dir()
-		sourcePath := filepath.Join(wd, s.Name)
-		relative, err := filepath.Rel(outputDir, sourcePath)
+		sourcePath := path.Join(wd, s.Name)
+		relative, err := path.ToSlash(filefile.Rel(outputDir, sourcePath))
 		if err != nil {
 			return nil, fmt.Errorf("failed to compute path of %s relative to %s: %w"+sourcePath, outputDir, err)
 		}