add comma to second keypoint

Author: Theo Geddes

_episodes/01-quickstart.md

@@ -20,7 +20,7 @@ keypoints:
 
 - "The purpose of the quickstart guide is to enable a user of ESMValTool
   to run ESMValTool as quickly as possible"
-- "Use the `module load` command to load the ESMValTool environment 
+- "Use the `module load` command to load the ESMValTool environment, 
   see the [installation]({{ page.root }}{% link _episodes/02-installation.md %}) 
   episode for more details and use `esmvaltool --help` to check the ESMValTool 
   environment"