@DaveLessnau
If you only need to format a handful of words as strikethrough text, you could hard-code them using a special Unicode character:
Combining Long Stroke Overlay (U+0336)
For example:
Code:
<p>This is s̶t̶r̶i̶k̶e̶t̶h̶r̶o̶u̶g̶h text.</p>
Obviously, this isn't a perfect solution.