Re: Emphasize the character to be typed next in *Completions*

[Richard Stallman]

    To emphasize the non-informative part is not useful, but a different
    face could be used to *de-emphasize* it.  (Even if emphasizing the
    word "de-emphasize" looks paradoxical, it's appropriate here :-)

That is true.  So perhaps what it should do is put one face on that part
and another face on the rest.

This way, there is no option to customize, but there are two faces
to customize.