convert-standard-filename documentation is insufficient

[Jari Aalto <jari.aalto@cante.net>]

Given following description:

    (convert-standard-filename FILENAME)

    Convert a standard file's name to something suitable for the
    current OS. This function's standard definition is trivial; it
    just returns the argument. However, on some systems, the function
    is redefined with a definition that really does change some file
    names.

This leaves completely open where function would be used.
Please provide concrete examples in the documentation string.

Jari