enum.c: suppress warnings

* enum.c (sliceafter_ii): suppress unused-value warnings.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@45990 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
io.c: update ARGF examples

* io.c (argf_each_line, argf_inplace_mode_set): [DOC] Update ARGF
  documentation examples.  `ARGF.lines` has been deprecated in
  favor of `ARGF.each_line`.  [Fixes GH-615]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@45991 b2dd03c8-39d4-4d8f-98ff-823fe69b080e