fix a typo

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@32543 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

doc/ChangeLog-1.9.3

@@ -405,7 +405,7 @@ Tue Jul  5 14:05:43 2011  NARUSE, Yui  <naruse@ruby-lang.org>
 
 	* lib/webrick/httpauth/digestauth.rb (_authenticate):
 	  Literal texts in HTTP ABNF is case-insensitive (RFC2616 2.1),
-	  and a ample implementation in RFC2617 also ignores the case
+	  and a sample implementation in RFC2617 also ignores the case
 	  of algorithms. So now this ignores those cases.
 	  [ruby-dev:43965] [Feature #4936]