Document stdin feature in cli help text

CMTegner · CMTegner · commit 45df9c6073c6 · 2014-08-17T15:05:15.000+02:00
diff --git a/bin/cli.js b/bin/cli.js
@@ -10,7 +10,7 @@ var args = require('nomnom')
     })
     .option('file', {
         position: 0,
-        help: 'The file containing the markup to convert to JSONML'
+        help: 'The file containing the markup to convert to JSONML, will read from stdin if not specified'
     })
     .option('version', {
         flag: true,
