Mention in rdoc that Diff::LCS::ContextChange can be converted to an …

…array

lib/diff/lcs.rb

@@ -181,6 +181,20 @@ def diff(seq1, seq2, callbacks = nil, &block) # :yields diff changes:
   # Class argument is provided for +callbacks+, #diff will attempt to
   # initialise it. If the +callbacks+ object (possibly initialised) responds
   # to #finish, it will be called.
+  #
+  # Each element of a returned array is a Diff::LCS::ContextChange object,
+  # which can be implicitly converted to an array.
+  #
+  #   Diff::LCS.sdiff(a, b).each do |action, (old_pos, old_element), (new_pos, new_element)|
+  #     case action
+  #     when '!'
+  #       # replace
+  #     when '-'
+  #       # delete
+  #     when '+'
+  #       # insert
+  #     end
+  #   end
   def sdiff(seq1, seq2, callbacks = nil, &block) #:yields diff changes:
     diff_traversal(:sdiff, seq1, seq2, callbacks || Diff::LCS::SDiffCallbacks,
                    &block)