Escaped tildes aren't treated as escaped

If you type something like ```markdown Test\~ Wow\~! ``` The site *should* render it as: > Test\~ Wow\~! However, it *instead* renders it as: > Test<s> Wow</s>! Curiously, this bug only shows up after a comment is **actually posted**; it's an observable difference between the renderer used in preview pane and the actual renderer.