https://docs.mongodb.com/mongoid/master/tutorials/mongoid-relations/#dependent-behavior lists a number of possible dependent options, but it does not list restrict_with_error which Mongoid also provides.
It appears that the values that are documented like `restrict` are not valid, therefore this ticket is to:
Compile the list of `dependent` values from code
Update documentation to reflect the actual values
Verify each value applies to each of the two association types (has_one/has_many) and note exceptions in documentation. For example, it appears that :delete_all may be inapplicable to has_one