Updated README.txt to match the content of the 2.x branch

git-svn-id: https://svn.apache.org/repos/asf/commons/proper/cli/branches/cli-1.x@712644 13f79535-47bb-0310-9956-ffa450edef68

Author: ebourg

README.txt

@@ -32,7 +32,8 @@ and to build and test the system use:
 
 The system will build and test itself.
 
-For complete documentation type:
+For complete documentation and to create a local copy of the
+CLI project website, type:
 
   mvn site