I've been writing documentation and I've already caught myself pressing ctrl + space a few times to try and get Word to autocomplete a long word for me.

I also do that, why is word processor intellisense not a thing yet.

I always do that when writing emails haha. I need auto complete in more places.

Works for me in vim

Just write the text inside your favorite IDE or text editor and reap some auto complete benefits. If you're using wiki for your documentation, copy and paste the text in and add in the formatting. Even if it does take you the same amount of time at least you're less stressed because you're in a comfortable environment.