Fix "C-h k" and "C-h c" with Paste from Kill Menu

* lisp/subr.el (event-basic-type, event-modifiers): Return nil if
EVENT is a string.  (Bug#62626)

lisp/subr.el

@@ -1520,6 +1520,7 @@ EVENT may be an event or an event type.  If EVENT is a symbol
 that has never been used in an event that has been read as input
 in the current Emacs session, then this function may fail to include
 the `click' modifier."
+  (unless (stringp event)
     (let ((type event))
       (if (listp type)
 	  (setq type (car type)))
@@ -1544,7 +1545,7 @@ the `click' modifier."
 	      (push 'super list))
 	  (or (zerop (logand type ?\A-\0))
 	      (push 'alt list))
-	list))))
+	  list)))))
 
 (defun event-basic-type (event)
   "Return the basic type of the given event (all modifiers removed).
@@ -1552,6 +1553,7 @@ The value is a printing character (not upper case) or a symbol.
 EVENT may be an event or an event type.  If EVENT is a symbol
 that has never been used in an event that has been read as input
 in the current Emacs session, then this function may return nil."
+  (unless (stringp event)
     (if (consp event)
         (setq event (car event)))
     (if (symbolp event)
@@ -1562,7 +1564,7 @@ in the current Emacs session, then this function may return nil."
         ;; cause `downcase' to get an error.
         (condition-case ()
 	    (downcase uncontrolled)
-	(error uncontrolled)))))
+	  (error uncontrolled))))))
 
 (defsubst mouse-movement-p (object)
   "Return non-nil if OBJECT is a mouse movement event."