Update README.md

README.md

@@ -1,14 +1,22 @@
 txexpr [![Build Status](https://travis-ci.org/mbutterick/txexpr.svg)](https://travis-ci.org/mbutterick/txexpr)
 ---------------
 
-Convenience functions for working with HTML-style tagged X-expressions in Racket 6.0+
+Convenience functions for working with HTML-style tagged X-expressions in Racket 6.0+.
 
 Install from the command line like so:
 
     raco pkg install txexpr
 
-Then require it in your Racket file:
+Then require it in your Racket file, in standard mode:
 
     (require txexpr)
+    
+In safe mode (with contracts):
+
+    (require (submod txexpr safe))
+
+Or in typed mode:
+
+    (require typed/txexpr)
 
 Full docs are installed with the package. You can also [read the docs here](http://pkg-build.racket-lang.org/doc/txexpr).