Remove eldoc-box-help-at-point

This function doesn't play well when eldoc-document-function is async.
Plus this function is not in ElDoc spec anyway.

README.org

@@ -8,7 +8,6 @@ Get the file, add to load path, and
 
 * Usage
 ** Function
--  =eldoc-box-help-at-point= :: Show the documentation of the symbol at point.
 - =eldoc-box-hover-mode= :: Show documentation upon hover. Note that you need to enable ElDoc mode for this to work.
 ** Face
 -  =eldoc-box-border= :: Adjust =:background= of this face for border color.

eldoc-box.el

@@ -92,17 +92,6 @@ Consider your machine's screen's resolution when setting this variable.")
 Consider your machine's screen's resolution when setting this variable.")
 
 ;;;;; Function
-
-(defun eldoc-box-help-at-point ()
-  "Display hover info at point in a childframe."
-  (interactive)
-  (let ((doc (funcall eldoc-documentation-function)))
-    (if doc
-        (progn
-          (eldoc-box--display doc)
-          (eldoc-box--inject-quit-func))
-      (message "No documentation available"))))
-
 (defvar eldoc-box--frame nil ;; A backstage variable
   "The frame to display doc.")