Add support for askama inline value handling #280

Hi, it seems like this crate does not handle inline value handling from askama. Take this example:

<div
        {%~ if some_flag ~%}data-some-value.foo-bar{%~ endif ~%}
        class="{{ module_name }}"
>

</div>

Running this with minhtml --preserve-brace-template-syntax --keep-closing-tags --preserve-chevron-percent-template-syntax yields to this: <div class="{{ module_name }}" endif if some_flag {%~ ~%} ~%}data-some-value.foo-bar{%~></div>. This breaks the assumed askama syntax