Update docs with a more portalbe command.

Author: cbrochtrup

docs/using-cli.md

@@ -171,7 +171,7 @@ The displayed help shows information about which Python component your command
 corresponds to, as well as usage information for how to extend that command.
 
 The environment variable, `FIRE_PAGER`, sets the default pager for help text
-to the preferred program. For example, set `FIRE_PAGER=cat` to print help text
+to the preferred program. For example, set `FIRE_PAGER=-` to print help text
 on standard out.