Fix #4784: browse-at-remote-prefer-symbolic = nil

+ Default browse-at-remote-prefer-symbolic to nil because a permanent
  URL is generally more desirable for developers sharing links.
+ 'SPC g y' and 'SPC o o' now support the prefix arg, which will negate
  the default value of browse-at-remote-prefer-symbolic for that call.

modules/emacs/vc/autoload/vc.el

@@ -5,6 +5,29 @@
         (cdr (browse-at-remote--get-url-from-remote (car url))))
       (user-error "Can't find homepage for current project")))
 
+(defvar browse-at-remote-prefer-symbolic)
+;;;###autoload
+(defun +vc/browse-at-remote (&optional arg)
+  "Open URL to current file (and line if selection is active) in browser.
+If prefix ARG, negate the default value of `browse-at-remote-prefer-symbolic'."
+  (interactive "P")
+  (let ((browse-at-remote-prefer-symbolic
+         (if arg
+             (not browse-at-remote-prefer-symbolic)
+           browse-at-remote-prefer-symbolic)))
+    (browse-at-remote)))
+
+;;;###autoload
+(defun +vc/browse-at-remote-kill (&optional arg)
+  "Copy URL to current file (and line if selection is active) to clipboard.
+If prefix ARG, negate the default value of `browse-at-remote-prefer-symbolic'."
+  (interactive "P")
+  (let ((browse-at-remote-prefer-symbolic
+         (if arg
+             (not browse-at-remote-prefer-symbolic)
+           browse-at-remote-prefer-symbolic)))
+    (browse-at-remote-kill)))
+
 ;;;###autoload
 (defun +vc/browse-at-remote-homepage ()
   "Open homepage for current project in browser."

modules/emacs/vc/config.el

@@ -100,7 +100,13 @@ otherwise in default state."
 
 
 (after! browse-at-remote
+  ;; It's more sensible that the user have more options. If they want line
+  ;; numbers, users can request them by making a selection first. Otherwise
+  ;; omitting them.
   (setq browse-at-remote-add-line-number-if-no-region-selected nil)
+  ;; Opt to produce permanent links with `browse-at-remote' by default,
+  ;; using commit hashes rather than branch names.
+  (setq browse-at-remote-prefer-symbolic nil)
 
   ;; HACK `browse-at-remote' produces urls with `nil' in them, when the repo is
   ;;      detached. This creates broken links. I think it is more sensible to