Issue #3014121 by Geordi, shreyakaushik11, anmolgoyal74, msankhala, rwohleb,...

 * been printed from being printed again. For example:

 * @code

 * <cat class="{{ attributes.class }} my-custom-class"{{ attributes|without('class') }}>

 *  {# Produces <cat class="cat black-cat white-cat black-white-cat my-custom-class" id="socks"> #}

 * @endcode

 * Produces:

 * @code

 * <cat class="cat black-cat white-cat black-white-cat my-custom-class" id="socks">

 * @endcode

 *

 * The attribute keys and values are automatically escaped for output with