Fix a code in the Array#min documentation.

array.c

@@ -5921,8 +5921,7 @@ ary_min_opt_string(VALUE ary, long i, VALUE vmin)
  *
  *  With an argument +n+ and a block, returns a new \Array with at most +n+ elements,
  *  in ascending order per the block:
- *    [0, 1, 2, 3].min(3) # => [0, 1, 2]
- *    [0, 1, 2, 3].min(6) # => [0, 1, 2, 3]
+ *    ['0', '00', '000'].min(2) {|a, b| a.size <=> b.size } # => ["0", "00"]
  */
 static VALUE
 rb_ary_min(int argc, VALUE *argv, VALUE ary)