doc: link to tutorial (#78)

Author: BurdetteLamar

doc/rexml/tutorial.rdoc

@@ -438,12 +438,10 @@ An element may have:
 
   Output:
 
-        p ele
     [REXML::Element, <book category='cooking'> ... </>]
     [REXML::Element, <book category='children'> ... </>]
     [REXML::Element, <book category='web'> ... </>]
     [REXML::Element, <book category='web' cover='paperback'> ... </>]
-    nil
 
 [Previous Element]
 
@@ -463,7 +461,6 @@ An element may have:
     [REXML::Element, <book category='web'> ... </>]
     [REXML::Element, <book category='children'> ... </>]
     [REXML::Element, <book category='cooking'> ... </>]
-    nil
 
 [Next Node]
 
@@ -489,7 +486,6 @@ An element may have:
     [REXML::Text, "\n\n"]
     [REXML::Element, <book category='web' cover='paperback'> ... </>]
     [REXML::Text, "\n\n"]
-    nil
 
 [Previous Node]
 
@@ -515,7 +511,6 @@ An element may have:
     [REXML::Text, "\n\n"]
     [REXML::Element, <book category='cooking'> ... </>]
     [REXML::Text, "\n\n"]
-    nil
 
 ==== Children
 

lib/rexml/rexml.rb

@@ -26,6 +26,8 @@
 # - REXML::Document.
 # - REXML::Element.
 #
+# There's also an {REXML tutorial}[doc/rexml/tutorial_rdoc.html].
+#
 module REXML
   COPYRIGHT = "Copyright © 2001-2008 Sean Russell <[email protected]>"
   DATE = "2008/019"