如何在golang标志中记录其余argv？

As a microservices author, I appreciate how powerful the standard library's flag pacakge is, providing a lightweight way to document command line flags. However, the built-in -help option appears to present documentation for only the flags themselves, while the rest of the command line arguments are often idiosyncratic, requiring documentation as well. What is a good way to document the rest of the CLI arguments, such as a Go application that accepts some flags, and then treats the rest of the arguments as file paths?

My preferred approach is just to set flag.Usage to a function which prints the additional documentation.

For example:

flag.Usage = func() {
    fmt.Fprintf(os.Stderr, "usage: %s [flags] <paths...>
", os.Args[0])
    flag.PrintDefaults()
    fmt.Fprintf(os.Stderr, "Argument documention goes here
")
}