tmpl:bind - multiple template files

[tylermmorton]

It would be useful to update the tmpl:bind utility to support multiple template files, either via glob or comma-separated lists.

func (t *DotContext) TemplateText() string {
	// TODO update tmpl:bind to generate something like this
	var files = []string{ ... }
	var buf = &bytes.Buffer{}

	for _, file := range files {
		byt, err := os.ReadFile(file)
		if err != nil {
			panic(err)
		}
		buf.Write(byt)
	}

	return buf.String()
}