DTD specializations for DITA Bootstrap Extension 5.3.2

DTD specializations for the DITA Bootstrap Extension plug-in 5.3.2 for DITA Bootstrap

The plug-in includes DTD handling for the following Bootstrap Extension components:

• Counter (<counter>)
• Parallax (<parallax>)
• Slider (<slider>)
• Whitebox (<whitebox>)

Full Changelog: https://github.com/dita-bootstrap/dita-bootstrap.extension.dtd/commits/5.3.2