Clarify face-at-point doc string and add (thing-at-point 'face)

* lisp/faces.el (face-at-point): Say what this function does.

* lisp/thingatpt.el (thing-at-point-face-at-point): Add `face'
type (bug#57087).
(thing-at-point-provider-alist, thing-at-point): Mention it in the
doc strings.

lisp/faces.el

@@ -2046,18 +2046,29 @@ as backgrounds."
     (when msg (message "Color: `%s'" color))
     color))
 
-(defun face-at-point (&optional thing multiple)
+(defun face-at-point (&optional text multiple)
-  "Return the face of the character after point.
+  "Return a face name from point in the current buffer.
-If it has more than one face, return the first one.
+This function is meant to be used as a conveniency function for
-If THING is non-nil try first to get a face name from the buffer.
+providing defaults when prompting the user for a face name.
-IF MULTIPLE is non-nil, return a list of all faces.
+
-Return nil if there is no face."
+If TEXT is non-nil, return the text at point if it names an
+existing face.
+
+Otherwise, look at the faces in effect at point as text
+properties or overlay properties, and return one of these face
+names.
+
+IF MULTIPLE is non-nil, return a list of faces.
+
+Return nil if there is no face at point.
+
+This function is not meant for handling faces programatically; to
+do that, use `get-text-property' and `get-char-property'."
   (let (faces)
-    (if thing
+    (when text
-        ;; Try to get a face name from the buffer.
+      ;; Try to get a face name from the buffer.
-        (let ((face (intern-soft (thing-at-point 'symbol))))
+      (when-let ((face (thing-at-point 'face)))
-          (if (facep face)
+        (push face faces)))
-              (push face faces))))
     ;; Add the named faces that the `read-face-name' or `face' property uses.
     (let ((faceprop (or (get-char-property (point) 'read-face-name)
                         (get-char-property (point) 'face))))

lisp/thingatpt.el

@@ -74,7 +74,7 @@ question.
 
 \"things\" include `symbol', `list', `sexp', `defun', `filename',
 `existing-filename', `url', `email', `uuid', `word', `sentence',
-`whitespace', `line', and `page'.")
+`whitespace', `line', `face' and `page'.")
 
 ;; Basic movement
 
@@ -166,7 +166,7 @@ positions of the thing found."
 THING should be a symbol specifying a type of syntactic entity.
 Possibilities include `symbol', `list', `sexp', `defun',
 `filename', `existing-filename', `url', `email', `uuid', `word',
-`sentence', `whitespace', `line', `number', and `page'.
+`sentence', `whitespace', `line', `number', `face' and `page'.
 
 When the optional argument NO-PROPERTIES is non-nil,
 strip text properties from the return value.
@@ -361,6 +361,15 @@ E.g.:
 
 (put 'existing-filename 'thing-at-point 'thing-at-point-file-at-point)
 
+;; Faces
+
+(defun thing-at-point-face-at-point (&optional _lax _bounds)
+  "Return the name of the face at point as a symbol."
+  (when-let ((face (thing-at-point 'symbol)))
+    (and (facep face) (intern face))))
+
+(put 'face 'thing-at-point 'thing-at-point-face-at-point)
+
 ;;  URIs
 
 (defvar thing-at-point-beginning-of-url-regexp nil