Add quotes to inline literals

Author: MrTango

docs/classic-ui/templates-global-variables.md

@@ -13,9 +13,9 @@ For convenience Plone defines a couple of global variables often used in templat
 - [portal_state](backend-global-utils-portal-state-label)
 - [`context_state`](backend-global-utils-context-state-label)
 - [`plone_view`](backend-global-utils-plone-view-label)
-- icons
-- lang
-- portal_url
-- checkPermission
-- ajax_include_head
-- isAnon
+- `icons`
+- `lang`
+- `portal_url`
+- `checkPermission`
+- `ajax_include_head`
+- `isAnon`