Fix typo in the "alias" example

Fix typo in the "alias" example

PR cli/17332, filed around 8 years ago, points out a typo in the docs
-- in one example, the command and its output are obviously out of
sync.  This patch fixes it.  I'm checking this in as obvious.

Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=17332