Updated documentation

Author: kmvanbrunt

CHANGELOG.md

@@ -7,6 +7,7 @@
 * Enhancements
     * Added `silent_startup_script` option to `cmd2.Cmd.__init__()`. If `True`, then the startup script's
       output will be suppressed. Anything written to stderr will still display.
+    * cmd2 now uses pyreadline3 when running Python 3.8 or greater on Windows  
 
 ## 1.4.0 (November 11, 2020)
 * Bug Fixes

docs/features/startup_commands.rst

@@ -64,3 +64,12 @@ like so::
 This text file should contain a :ref:`Command Script
 <features/scripting:Command Scripts>`. See the AliasStartup_ example for a
 demonstration.
+
+You can silence a startup script's output by setting ``silent_startup_script``
+to True::
+
+    cmd2.Cmd.__init__(self, startup_script='.cmd2rc', silent_startup_script=True)
+
+Anything written to stderr will still print. Additionally, a startup script
+cannot be silenced if ``allow_redirection`` is False since silencing works
+by redirecting a script's output to ``os.devnull``.