E0715: A Layout type wraps no folder

In vuka 1 a folder declaring type Layout struct wrapped the pages below it. A folder's layout is its _layout.vuka.html now, the struct it declares (or, beside its markup alone, a Layout declared in Go). A Layout in a folder without one wraps nothing, so it is this error, at the type; a 1.x layout.vuka.html beside it is renamed _layout.vuka.html.

Wrong

// pages/layout.go
package pages

type Layout struct {
	Children ui.Node
}

func (l Layout) Render(ctx context.Context, w io.Writer) error { … }

Right

<!-- pages/_layout.vuka.html -->
<script lang="go">
package pages

import "github.com/vuka-lang/ui/v2"

type Layout struct {
	Children ui.Node
}
</script>

<html lang="en">
<body><main>{Children}</main></body>
</html>