Update Replit embeds to use replit.com (#483)

Replit moved from repl.it to replit.com

Author: masad-frost

lib/onebox/engine/replit_onebox.rb

@@ -6,7 +6,7 @@ class ReplitOnebox
       include Engine
       include StandardEmbed
 
-      matches_regexp(/^https?:\/\/repl\.it\/.+/)
+      matches_regexp(/^https?:\/\/(replit\.com|repl\.it)\/.+/)
       always_https
 
       def placeholder_html