(enriched-face-ans): For a `foreground-color'

(enriched-face-ans): For a `foreground-color'
property, return '(("x-color" COLOR))' so that COLOR will be
output as a parameter of the x-color annotation.  Likewise for the
`background-color' property.  In the case of normal face
properties, don't return annotations for unspecified foreground
and background face attributes.