Merge pull request #3397 from jekyll/recommend-pgrep-with-kill

Fixes #3339 Add `pkill -f jekyll` to ways to kill.

lib/jekyll/commands/serve.rb

@@ -50,7 +50,7 @@ module Jekyll
           if options['detach'] # detach the server
             pid = Process.fork { s.start }
             Process.detach(pid)
-            Jekyll.logger.info "Server detached with pid '#{pid}'.", "Run `kill -9 #{pid}' to stop the server."
+            Jekyll.logger.info "Server detached with pid '#{pid}'.", "Run `pkill -f jekyll' or `kill -9 #{pid}' to stop the server."
           else # create a new server thread, then join it with current terminal
             t = Thread.new { s.start }
             trap("INT") { s.shutdown }