Strike out using ~ not reflecting on fastpages

I am referring to this blog post of mine. So I struck out a word using the markdown way (with ~). But it is not getting reflected on fastpages as you can see in the following snapshot:

It is appearing perfectly on the associated Colab Notebook though.

Suggestions?

Try using HTML instead of markdown. In the title

It works in titles, thanks Hamel. However, the caveat there is the ToC now gets a go without it:

That’s interesting … this happens when you use HTML? Could be a limitation of the TOC Jekyll Extension

Yes, this happens when I use HTML in the heading. Here’s the link.