The search doesn’t care about the single s. The minimum word length applies, and Relevanssi disregards the single s. Searching for who's is essentially the same as searching for who.
Highlighting is another thing, and doesn’t care about the minimum length.
I just tested this on my site – while searching for who's finds all sorts of garbage at first, when I add the word to a post, only that one post is returned. Relevanssi works as it should.
However, in your case, the site is in English, and likely has the word “who” in almost all posts, and quite likely it’s a stopword, too – in that case the results will be random garbage. It’s not a particularly useful search term.
I think I have a question in this same vein… We have a church site that has lots of different content types. One particular instance we had with the default WordPress search was when users searched for “mens” (as in “Men’s Ministry”), the search returns zero results. I’ve installed Relevanssi to see if the fuzzy search would help (I went ahead and toggled the “Always” option), but it appears that its still not grabbing those event posts. If I search “men’s” then it works as expected. Also, if I search “mens ministry” I just get all of the entries that have “ministry” in them, but not just “men’s ministry” posts. (this is an improvement over the default wp search, as “mens ministry” also returns zero results.)
Is there something I’m missing that should allow “mens” to return “men’s” results?
Relevanssi doesn’t understand language and doesn’t know “mens” means “men’s”. Fuzzy search doesn’t work either, because it doesn’t know how to remove parts of the word.
If you’re using OR as the search operator, a quick solution is to add the synonym “mens = men”.
