bug#15940: 24.3.50; doc string of `lwarn' refers to undefined variables

[Glenn Morris]

Eli Zaretskii wrote:

>> Would it make sense for the help system to always load the package an
>> autoloaded function is defined in?  Especially if the doc string refers
>> to other `...' items?
>
> Why not simply auto-load those variables, especially if the doc string
> refers to them?

Because this is a general problem that comes up again and again,
and papering over it with manual autoloads every time seems like bad
practice.

A change was added for this in 24.3:

    *** `C-h f' (`describe-function') can now perform autoloading.
    When this command is called for an autoloaded function whose docstring
    contains a key substitution construct, that function's library is
    automatically loaded, so that the documentation can be shown
    correctly.  To disable this, set `help-enable-auto-load' to nil.

It needs to be generalized somehow.

I'm pretty sure this has been discussed multiple times in the past,
so there's probably an idea/implementation out there somewhere in the
archives.