Merge RDoc changes from HEAD.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_1_8@10679 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

lib/readbytes.rb

@@ -1,22 +1,22 @@
-# readbytes.rb
-#
-# add IO#readbytes, which reads fixed sized data.
-# it guarantees read data size.
+# TruncatedDataError is raised when IO#readbytes fails to read enough data.
 
 class TruncatedDataError<IOError
-  def initialize(mesg, data)
+  def initialize(mesg, data) # :nodoc:
     @data = data
     super(mesg)
   end
+
+  # The read portion of an IO#readbytes attempt.
   attr_reader :data
 end
 
 class IO
-  # reads exactly n bytes from the IO stream.
-  # If the data read is nil, raises EOFError.
-  # If the data read is too short, raises TruncatedDataError.
-  # The method TruncatedDataError#data may be used to obtain
-  # the truncated message.
+  # Reads exactly +n+ bytes.
+  #
+  # If the data read is nil an EOFError is raised.
+  #
+  # If the data read is too short a TruncatedDataError is raised and the read
+  # data is obtainable via its #data method.
   def readbytes(n)
     str = read(n)
     if str == nil