Fix logs containing IPv6 URLs (#9813)

Merge pull request 9813

lib/jekyll/commands/serve.rb

@@ -243,7 +243,7 @@ module Jekyll
         def format_url(ssl_enabled, address, port, baseurl = nil)
           format("%<prefix>s://%<address>s:%<port>i%<baseurl>s",
                  :prefix  => ssl_enabled ? "https" : "http",
-                 :address => address,
+                 :address => address.include?(":") ? "[#{address}]" : address,
                  :port    => port,
                  :baseurl => baseurl ? "#{baseurl}/" : "")
         end

lib/jekyll/commands/serve/live_reload_reactor.rb

@@ -55,8 +55,9 @@ module Jekyll
               EM.schedule { @started_event.set }
               EM.add_shutdown_hook { @stopped_event.set }
 
+              host = opts["host"].include?(":") ? "[#{opts["host"]}]" : opts["host"]
               Jekyll.logger.info "LiveReload address:",
-                                 "http://#{opts["host"]}:#{opts["livereload_port"]}"
+                                 "http://#{host}:#{opts["livereload_port"]}"
             end
           end
           @thread.abort_on_exception = true