Strings in HTML must be sanitized

[letil]

The \ns in multiline texts in html need to be replaced with \\n

<div>
  Hello
  World
</div>

generates

  tdiv:
    text "Hello
  World"

but expected

  tdiv:
    text "Hello\nWorld"

[letil]

The expected result can be as following too:

  tdiv:
    text """Hello
  World"""

[letil]

The strings with " need to be sanitized too