[DOC] leap seconds [ci skip]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@64597 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

ext/date/date_core.c

@@ -6788,7 +6788,7 @@ date_strftime_internal(int argc, VALUE *argv, VALUE self,
  *
  *      %M - Minute of the hour (00..59)
  *
- *      %S - Second of the minute (00..59)
+ *      %S - Second of the minute (00..60)
  *
  *      %L - Millisecond of the second (000..999)
  *      %N - Fractional seconds digits, default is 9 digits (nanosecond)
@@ -8233,7 +8233,7 @@ dt_lite_to_s(VALUE self)
  *
  *      %M - Minute of the hour (00..59)
  *
- *      %S - Second of the minute (00..59)
+ *      %S - Second of the minute (00..60)
  *
  *      %L - Millisecond of the second (000..999)
  *      %N - Fractional seconds digits, default is 9 digits (nanosecond)