With a trivial raise, e.g.,
the formatter knows to check if there is a class named
`Error' and turn the display of the class name in the
exceptions section into an HREF pointing to that class'
For non-trivial raises, e.g.,
raise Error, "unknown command"
raise Error("unknown command")
the formatter prints the arguments to the raise
function (a great feature by the way), but does not
know enough to notice the first token is a class name
and put the appropriate HREF.