fix: validate undefined variables in initHelp template (#150)

Co-authored-by: rchojn <[email protected]>

pkg/recipe/sauce.go

@@ -1,6 +1,7 @@
 package recipe
 
 import (
+	"errors"
 	"fmt"
 	"path/filepath"
 	"strings"
@@ -169,5 +170,11 @@ func (s *Sauce) RenderInitHelp() (string, error) {
 		return "", fmt.Errorf("failed to render initHelp template: %w", err)
 	}
 
-	return buf.String(), nil
+	output := buf.String()
+
+	if strings.Contains(output, "<no value>") {
+		return "", errors.New("some of the variables used in the initHelp template were undefined")
+	}
+
+	return output, nil
 }