Ruby

• string.c: Fix the ambiguous description of the behavior of
  rb_str_aref_m with a range. It returns nil when the beginning of
  the range is greater than the end of the string rather than the range.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@31962 b2dd03c8-39d4-4d8f-98ff-823fe69b080e