[core] remove jump-to-reference from core-jump

we don't need it and it doesn't work

core/core-jump.el

@@ -55,29 +55,6 @@ handlers can be added. MODE must be a major mode."
            "gg" 'spacemacs/jump-to-definition
            "gG" 'spacemacs/jump-to-definition-other-window)))))
 
-(defmacro spacemacs|define-reference-handlers (mode &rest handlers)
-  "Defines reference handlers for the given MODE.
-This defines a variable `spacemacs-reference-handlers-MODE' to which
-handlers can be added, and a function added to MODE-hook which
-sets `spacemacs-reference-handlers' in buffers of that mode."
-  (let ((mode-hook (intern (format "%S-hook" mode)))
-        (func (intern (format "spacemacs//init-reference-handlers-%S" mode)))
-        (handlers-list (intern (format "spacemacs-reference-handlers-%S" mode))))
-    `(progn
-       (defvar ,handlers-list ',handlers
-         ,(format (concat "List of mode-specific reference handlers for %S. "
-                          "These take priority over those in "
-                          "`spacemacs-default-reference-handlers'.")
-                  mode))
-       (defun ,func ()
-         (setq spacemacs-reference-handlers
-               (append ,handlers-list
-                       spacemacs-default-reference-handlers)))
-       (add-hook ',mode-hook ',func)
-       (with-eval-after-load 'bind-map
-         (spacemacs/set-leader-keys-for-major-mode ',mode
-           "gr" 'spacemacs/jump-to-reference)))))
-
 (defun spacemacs//get-jump-handlers ()
   "Combine all jump handlers into a list.
 
@@ -121,43 +98,12 @@ They are in order: `spacemacs-jump-handlers',
     (goto-char pos)
     (spacemacs/jump-to-definition)))
 
-(defun spacemacs/jump-to-reference ()
-  "Jump to reference around point using the best tool for this action."
-  (interactive)
-  (catch 'done
-    (let ((old-window (selected-window))
-          (old-buffer (current-buffer))
-          (old-point (point)))
-      (dolist (-handler spacemacs-reference-handlers)
-        (let ((handler (if (listp -handler) (car -handler) -handler))
-              (async (when (listp -handler)
-                       (plist-get (cdr -handler) :async))))
-          (ignore-errors
-            (call-interactively handler))
-          (when (or (eq async t)
-                    (and (fboundp async) (funcall async))
-                    (not (eq old-point (point)))
-                    (not (equal old-buffer (window-buffer old-window))))
-            (throw 'done t)))))
-    (message "No reference handler was able to find this symbol.")))
-
-(defun spacemacs/jump-to-reference-other-window ()
-  "Jump to reference around point in other window."
-  (interactive)
-  (let ((pos (point)))
-    ;; since `spacemacs/jump-to-reference' can be asynchronous we cannot use
-    ;; `save-excursion' here, so we have to bear with the jumpy behavior.
-    (switch-to-buffer-other-window (current-buffer))
-    (goto-char pos)
-    (spacemacs/jump-to-reference)))
-
 ;; Set the `:jump' property manually instead of just using `evil-define-motion'
 ;; in an `eval-after-load' macro invocation because doing that prevents
 ;; `describe-function' from correctly finding the source.
 ;;
 ;; See discussion on https://github.com/syl20bnr/spacemacs/pull/6771
 (with-eval-after-load 'evil
-  (evil-set-command-property 'spacemacs/jump-to-definition :jump t)
-  (evil-set-command-property 'spacemacs/jump-to-reference :jump t))
+  (evil-set-command-property 'spacemacs/jump-to-definition :jump t))
 
 (provide 'core-jump)