create: Fix typo in error message

create/content.go

@@ -95,7 +95,7 @@ func NewContent(h *hugolib.HugoSites, kind, targetPath string, force bool) error
 		}
 
 		if ext == "" {
-			return "", fmt.Errorf("failed to resolve %q to a archetype template", targetPath)
+			return "", fmt.Errorf("failed to resolve %q to an archetype template", targetPath)
 		}
 
 		if !files.IsContentFile(b.targetPath) {