If I am not misunderstanding your questions, it should be pretty easy. Go to Tools>Configuration>Friendly URLS and change "Suffix for friendly URLs:" to "/". That is what I did. Then every Doc ends in "/", not just the parent/child folders.

# Rewrite ".../page.html" to ".../" (with a permanent redirect)
RewriteCond %{REQUEST_FILENAME} !-f
RewriteRule ^([^\.]+)\.html$ $1/ [R=301,L]