[Fix #3071] Use xref to push point to marker stack

xref-push-marker-stack is the up-to-date way of pushing point to marker
stack. This should be used instead of find-tag-marker ring that has been
marked as obsolete in emacs 25.1 (https://github.com/emacs-mirror/emacs/blob/3af9e84ff59811734dcbb5d55e04e1fdb7051e77/lisp/progmodes/etags.el#L184)

Author: sktoiva

cider-common.el

@@ -28,7 +28,7 @@
 (require 'cider-compat)
 (require 'nrepl-dict)
 (require 'cider-util)
-(require 'etags) ; for find-tags-marker-ring
+(require 'xref)
 (require 'tramp)
 
 (defcustom cider-prompt-for-symbol nil
@@ -151,7 +151,7 @@ If a symbol, `cider-jump-to' searches for something that looks like the
 symbol's definition in the file.
 If OTHER-WINDOW is non-nil don't reuse current window."
   (with-no-warnings
-    (ring-insert find-tag-marker-ring (point-marker)))
+    (xref-push-marker-stack))
   (if other-window
       (pop-to-buffer buffer 'display-buffer-pop-up-window)
     (pop-to-buffer buffer cider-jump-to-pop-to-buffer-actions))