[ElMiko]

Because, Kevin H, "wont" and "cant" are actually words, so relying on spellcheck will fail to catch instances where these are legitimately erroneous. It also serves as a mental flag that always me that if there are these kinds of apostrophe errors, there's may be others (and therefore I should run some of my other "missing apostrophe" searches). And as to why I want it to be inserted rather than an insertion AND replacement, because there are other types of missing apostrophe errors that don't end in "t", and I'd like to combine them into a single search with a universal replacement value... Namely, a single apostrophe.

But here's the thing, it might simply be more helpful to just consider my question conceptually, rather than practically. Regardless of whether you understand or agree with my reasoning for wanting to create this kind of search, the question is fundamentally about what is possible within regex. Specifically matching (and replacing) liminal spaces between characters.

I actually have an idea that I've used in other contexts, but I'm away from the puter. It involves using (|\s)