Re: new *Help* argument highlighting

[Richard Stallman <rms@gnu.org>]

    > So he can customize two things instead of one.  That is no big deal.
    > (Only a few people will customize this.)

    I'm not entirely sure whether that means "OK, let's use lowercase
    italics and have a face and a -function var", or I'm just misreading
    English again :)

To say that a user can customize something does not necessarily mean
introducing a defcustom to customize it.  That is one of many
customization mechanisms in Emacs.  Another customization mechanism
is to redefine a function.

Some customizations are natural to do in that way, and some are
important enough to be worth installing a defcustom for.  But we
should refuse to fall into thinking automatically "add a defcustom"
whenever we think something might want to be changed by some users.
Many of those things are definitely not worth adding a defcustom for.

I am not sure what is the best way to recommend users deal with
customizing this, when they want to customize this.  It depends
on how often anyone will want to change that.  That depends
on other things.

    I think the least we can do is make lowercasing depending on whether
    face-differs-from-default-p returns true.

    If it does what I think it does.

Detecting automatically when to do this is much better than adding a
separate defcustom to control whether to downcase.

(Meanwhile, in the long term, we also have the idea of defining a new
way to indicate variable names in doc strings.  With that, it won't be
a matter of downcasing any more.  But the issue of deciding whether to
upcase will replace it.)