The registration page's already-logged-in branch returned a bare
sentence with nowhere to go, leaving the visitor to find their own way
to their account. The invited-student branch a few lines above already
built exactly the link that was missing.
Extract that into continueLink() and use it for both logged-in
outcomes. There is deliberately still no wp_login_url() fallback:
sending someone already signed in to the login screen is the same dead
end with extra steps, so with no page configured there is no link.
Both messages now carry the us-register-form wrapper and enqueue the
plugin stylesheet, which the invite branch emitted markup for but never
loaded.
Closes#131
thatguygriff
abb2038bfa