Add additional examples to method/rs.reconfig page

Currently https://docs.mongodb.com/manual/reference/method/rs.reconfig/#examples only covers configuration changes to member properties such as priority.

It would be valuable to include additional example of how to update the setting values such as : chainingAllowed, heartbeatIntervalMillis, heartbeatTimeoutSecs in the "settings" of the config document.

Ref : https://gist.github.com/ianf-mongodb/e6827d1b11720e774745cdf3879c5984#file-getlasterrordefaultstestcase-sh