Work out how to render element HTML without needing |raw twig filter

Problem/Motivation

It shouldn't be necessary to use the |raw argument when using the CDATA option.

Steps to reproduce

Use the CDATA option in a plugin.

Proposed resolution

Fix the output so that it can be filtered for XSS but still render HTML tags.

Remaining tasks

Solve the problem.

User interface changes

n/a

API changes

TBD

Data model changes

n/a