func (htmlDoc *htmlDocument) append(e element) {
	htmlDoc.elements = append(htmlDoc.elements, e)
}
append appends an element to the htmlDocument.
package gohtml
import "bytes"
var LineWrapColumn = 0
var LineWrapMaxSpillover = 5
type htmlDocument struct {
	elements []element
}
func (htmlDoc *htmlDocument) html() string {
	return string(htmlDoc.bytes())
}
func (htmlDoc *htmlDocument) bytes() []byte {
	bf := &formattedBuffer{
		buffer: &bytes.Buffer{},
		lineWrapColumn:       LineWrapColumn,
		lineWrapMaxSpillover: LineWrapMaxSpillover,
		indentString: defaultIndentString,
		indentLevel:  startIndent,
	}
	isPreviousNodeInline := true
	for _, child := range htmlDoc.elements {
		isPreviousNodeInline = child.write(bf, isPreviousNodeInline)
	}
	return bf.buffer.Bytes()
}