Add full stop

Author: liamjberrisford

contributing/roles.ipynb

@@ -51,7 +51,7 @@
     "    - Flag issues to the workshop lead. \n",
     "    - Remind participants to sign the register. \n",
     "    - Prompt the workshop lead to include regular breaks and keep to time. \n",
-    "- If you are unexpectedly unavailable to support delivery of the session while the programme administrator is unavailable, contact the programme directors in the first instance (Dr Fliss Guest & Dr Eilis Hannon), copying in the Coding for Reproducible Research mailbox, so that alternative arrangements can be made\n",
+    "- If you are unexpectedly unavailable to support delivery of the session while the programme administrator is unavailable, contact the programme directors in the first instance (Dr Fliss Guest & Dr Eilis Hannon), copying in the Coding for Reproducible Research mailbox, so that alternative arrangements can be made.\n",
     "\n",
     "### After a workshop\n",
     "- Provide feedback to the workshop lead on how the workshop went, common issues that might be useful for next time. \n",