Re: Nested sit-for's

[Richard Stallman]

    AFAICS, current-idle-time is used exactly once in the Emacs sources
    (in jit-lock.el), so I'm not entirely sure what convenience are you
    talking about; to my eyes it just adds a tiny bit of unneeded
    complexity to the function's interface...

I think it is good to make it easy to test whether Emacs is idle,
given that the function already exists and does this.  So I will document
the current behavior when Emacs is not idle.

As far as I can see, jit-lock-stealth-fontify is only
called when Emacs is idle, so it does not need to be changed.