Use faces to indicate states in Customize?

[Drew Adams]

With an aim to reduce the "noise" in the Customize UI a bit, here is a
proposal that might or might not be considered for 22.1. It should be
trivial to implement, while waiting for any more substantial UI
changes that we might make after 22.1.

1) We reduce the text displayed as the "state" of each option.

2) We use a slightly different face for each possible state, with the
   states that we want to stand out more (e.g. Set) having faces that
   stand out a little more.

That is, the face of the text would be different for each option
state, and the text would be simpler (shorter) than it is now. For
example (each entry here is (1) proposed text, (2) state, (3) current
text, (4) doc string text from `custom-magic-alist'):

 - 1) "Edited"; 2) `modified'; 3) "you have edited the value as text,
   but you have not set the option"; 4) "This item is modified, and
   has a valid form"

 - 1) "Saved" or possibly "Unchanged"; 2) `saved'; 3) "this option has
   been set and saved"; 4) "This item is marked for saving"

 - 1) "Standard"; 2) `standard'; 3) "this option is unchanged from its
   standard setting"; 4) "This item is unchanged from the standard
   setting"

 - 1) "Set Here"; 2) `set'; 3) "you have set this option, but not
   saved it for future sessions"; 4) "This item has been set but not
   saved"

 - 1) "Set Elsewhere"; 2) `changed'; 3) "this option has been changed
   outside the customize buffer"; 4) "The current value of this item
   has been changed temporarily"

 - 1) "Invalid"; 2) `invalid'; 3) "the value displayed for this option
   is invalid and cannot be set"; 4) "This item is modified, but has
   an invalid form"

 - 1) "Other"; 2) `rogue'; 3) "this option has not been changed with
   customize"; 4) "This item has no customization information"

This would make scanning for changes (Set) easier, and would make the
unchanged stuff (Unchanged, Standard) less prominent.

The default face differences should be slight, so that this does not
just make for _more_ noise. The faces used for each state should of
course be customizable. The more lengthy description could be
incorporated into tooltips.

What do you think?