(set-face-attribute):

(set-face-attribute):
  Update doc string.
(face-attribute-name-alist):
  Add :inherit.
(face-valid-attribute-values):
  Handle :inherit.
(face-read-string):
  Rephrase prompt to be less confusing.
  Assume that DEFAULT is a string, since we must return a string.
(face-read-integer):
  Use `format' to turn DEFAULT into an acceptable default for face-read-string.
  Match NEW-VALUE against the string "unspecified", not the symbol
    `unspecified', since that's what face-read-string returns.
(read-face-attribute):
  Lookup a name for old-value in valid, and use it as a default if we find one.
  Treat all values from face-read-string as strings.
  If the default is used, don't do any more processing on the value,
    just use the old value directly.
(read-face-and-attribute, modify-face):
  Tweak prompt.
(read-face-name):
  Don't assume prompt ends with a space.