There has been some effort to create a machine generated list of assertion codes. See https://github.com/mongodb/mongo/blob/r2.6.0/docs/errors.md for an example of the current state of this and https://jira.mongodb.org/browse/DOCS-1519 for the relevant documentation ticket.
Having a machine generated list of the command line options and all their attributes (allowed in config file, allowed in command line, positional, default values, etc.) in a machine parseable format would serve a similar purpose. It would allow for easier documentation of the options in a way that is inherently in sync with the server.
This could be done, for example, by having a hidden option to dump all command line option information, having a command to dump all option information, or even by having some external script read the source code in the same way the assertion codes are collected now.