use backticks for $ORG otherwise it triggers mathjax rendering (#360)

Author: Carreau

spec-0008/index.md

@@ -71,7 +71,7 @@ Elevating permissions beyond this should be done at the job level by redefining
 GitHub allows restricting the actions that workflows can use via the repository actions permissions settings at `https://github.com/$ORG/$PROJECT/settings/actions`.
 A reasonable default is to select the
 
-- Allow $ORG, and select non-$ORG, actions and reusable workflows
+- Allow `$ORG`, and select `non-$ORG`, actions and reusable workflows
 
 option and the suboptions: