Adapt to new kernel-execute API

This is required to avoid wrong-number-of-arguments error,
unlike javascript.

lisp/ein-cell.el

@@ -910,7 +910,8 @@ Called from ewoc pretty printer via `ein:cell-insert-output'."
    :clear_output   (cons #'ein:cell--handle-clear-output   cell)
    :set_next_input (cons #'ein:cell--handle-set-next-input cell)))
 
-(defmethod ein:cell--handle-execute-reply ((cell ein:codecell) content)
+(defmethod ein:cell--handle-execute-reply ((cell ein:codecell) content
+                                           -metadata-not-used-)
   (ein:cell-set-input-prompt cell (plist-get content :execution_count))
   (ein:cell-running-set cell nil)
   (let ((events (oref cell :events)))
@@ -931,7 +932,8 @@ Called from ewoc pretty printer via `ein:cell-insert-output'."
 ;; EWOC is connected in complicated way, I will leave them in
 ;; ein-cell.el.
 
-(defmethod ein:cell--handle-output ((cell ein:codecell) msg-type content)
+(defmethod ein:cell--handle-output ((cell ein:codecell) msg-type content
+                                    -metadata-not-used-)
   (let* ((json (list :output_type msg-type)))
     (ein:case-equal msg-type
       (("stream")
@@ -966,7 +968,8 @@ Called from ewoc pretty printer via `ein:cell-insert-output'."
   json)
 
 
-(defmethod ein:cell--handle-clear-output ((cell ein:codecell) content)
+(defmethod ein:cell--handle-clear-output ((cell ein:codecell) content
+                                          -metadata-not-used-)
   (ein:cell-clear-output cell
                          (plist-get content :stdout)
                          (plist-get content :stderr)

lisp/ein-kernel.el

@@ -548,7 +548,7 @@ as a string and the rest of the argument is the optional ARGS."
   (ein:kernel-execute
    kernel
    code
-   (list :output (cons (lambda (packed msg-type content)
+   (list :output (cons (lambda (packed msg-type content -metadata-not-used-)
                          (let ((func (car packed))
                                (args (cdr packed)))
                            (when (equal msg-type "stream")

lisp/ein-pytools.el

@@ -108,7 +108,7 @@ If OTHER-WINDOW is non-`nil', open the file in the other window."
    (list
     :output
     (cons
-     (lambda (packed msg-type content)
+     (lambda (packed msg-type content -metadata-not-used-)
        (destructuring-bind (kernel object other-window notebook-buffer)
            packed
          (ein:case-equal msg-type

lisp/ein-shared-output.el

@@ -62,7 +62,7 @@
   (ein:cell-execute-internal cell kernel code :silent nil))
 
 (defmethod ein:cell--handle-output ((cell ein:shared-output-cell)
-                                    msg-type content)
+                                    msg-type content -metadata-not-used-)
   (ein:log 'info "Got output '%s' in the shared buffer." msg-type)
   (when (oref cell :popup)
     (pop-to-buffer (ein:shared-output-create-buffer)))