Old-style backquote syntax

[Richard Stallman]

    *** 135,141 ****
      `c-old-style-variable-behavior' that changes this, though).")
            ,@(plist-put
             args ':type
    !    `(` (radio
                  (const :tag "Use style settings"
                         set-from-style)
                  ,(, (let ((type (eval (plist-get args ':type))))

That is the old-style backquote syntax.
(` ...) is equivalent to `...
and (, ...) is equivalent to ,...

If you want to change that to new-style backquote syntax,
please do.  But don't put a backslash in front of the `.

While it is nice to replace the old-style syntax,
we cannot drop support of it.  It must keep working.