I just spent 10 minutes not being able to find Customize any text in Discourse.
It turns out that I was searching “customize text howto” rather than “customize text how-to”.
Somehow I’ve not learned this in 7 years. If it’s possible to somehow make #howto be a synonym for #how-to it could help some people. But if you’re patient and type just “#how” it will recommend the proper tag. So this might be an example of how you just can’t help some people.
For you my friend I think we can make that change. 
howto
Seems the synonym does not work in search
Search results for '#howto' - Discourse Meta
I make a bold claim 
howto isn’t a synonym for how-to. It is a tag itself.
I was totally wrong, I reckon. I tried at my forum and search doesn’t recoqnize synonyms (…anymore; I’m quite sure that wasn’t situation earlier)
I’m starting to think that the tag was once called howto and then got renamed to how-to, and then someone else created another tag called howto.
That would explain how I linked to a search with howto in it and why I am now unable to find any howto topics.
But that’s just wild conjecture.