this is such an amazing plugin.
my suggestion is that you add a 'ignore underscores' button because i think they should be treated as spaces and not as connectors
this real URL that uses a underscore is not redirected by this plugin:
but this version with a hyphen (this is not a real url but entering it triggers the automatic redirection)
properly redirects to this page
is not redirecting but using a hyphen again makes it work
it goes properly to
so treating hyphens and underscores the same is my new feature request.