introspection.help

Return the name, signatures and help text for the registered methods on
the server. With no parameters, returns an ARRAY of STRUCTs. With an ARRAY
parameter, expects all elements to be of type STRING and specify method
names, with the return value being an ARRAY of STRUCT for the named methods
(in order). If the parameter is a single STRING type, the return value is
a STRUCT for the named method.

Each STRUCT will have the following members:

        name       A STRING containing the method name
        version    A STRING version stamp. Empty if none was specified.
        signature  An ARRAY containing the signatures, each an ARRAY of STRING
        help       A STRING containing the help text for the method

Note that an ARRAY is returned for the signatures even when there is only one
signature.