Make session persistence module agnostic

They've been removed from feature/workspaces and moved into
core/autoload/sessions, which falls back to desktop.el if persp-mode
isn't present. This also offers a substantial speed up to
restart+restoring and restoring sessions in general.

Also fixes #1210, where the newly spawned frame after doom/restart
wasn't focused.

Introduces the following commands:

- doom/restart
- doom/restart-and-restore
- doom/quickload-session
- doom/quicksave-session
- doom/load-session
- doom/save-session
- +workspace/restore-last-session (alias for doom/quickload-session)

And removes

- +workspace/load-session
- +workspace/save-session
- +workspace/load-last-session (renamed to +workspace/restore-last-session)
- +workspace/restart-emacs-then-restore (replaced by doom/restart-and-restore)
- :ss (ex command)
- :sl (ex command)

modules/feature/workspaces/config.el

@@ -5,11 +5,6 @@
 ;; it because it was unstable and slow; `persp-mode' is neither (and still
 ;; maintained).
 ;;
-;; By default, sessions are autosaved, but not autoloaded. Use :ss or
-;; `+workspace/save-session' to save, and :sl or `+workspace/load-session' to
-;; load the last autosaved session. You can give sessions a custom name so they
-;; can be loaded later.
-;;
 ;; NOTE persp-mode requires `workgroups' for file persistence in Emacs 24.4.
 
 (defvar +workspaces-main "main"
@@ -20,11 +15,6 @@
 `counsel-projectile-switch-project'. This function must take one argument: the
 new project directory.")
 
-;; FIXME actually use this for wconf bookmark system
-(defvar +workspaces-data-file "_workspaces"
-  "The basename of the file to store single workspace perspectives. Will be
-stored in `persp-save-dir'.")
-
 (defvar +workspaces-on-switch-project-behavior 'non-empty
   "Controls the behavior of workspaces when switching to a new project.
 
@@ -35,11 +25,10 @@ t           Always create a new workspace for the project
             associated with it.
 nil         Never create a new workspace on project switch.")
 
-;; If emacs is passed --restore, restore the last session on startup. This is
-;; used by the `+workspace/restart-emacs-then-restore' command.
-(defun +workspaces-restore-last-session (&rest _)
-  (add-hook 'emacs-startup-hook #'+workspace/load-session :append))
-(add-to-list 'command-switch-alist (cons "--restore" #'+workspaces-restore-last-session))
+;; FIXME actually use this for wconf bookmark system
+(defvar +workspaces-data-file "_workspaces"
+  "The basename of the file to store single workspace perspectives. Will be
+stored in `persp-save-dir'.")
 
 
 ;;
@@ -64,29 +53,29 @@ workspace. Also ensures that the *Warnings* buffer will be visible in main.
 
 Uses `+workspaces-main' to determine the name of the main workspace."
     (unless persp-mode
-      (persp-mode +1))
-    (unless noninteractive
-      (let (persp-before-switch-functions persp-activated-functions)
-        (with-selected-frame frame
-          ;; The default perspective persp-mode creates (`persp-nil-name') is
-          ;; special and doesn't represent a real persp object, so buffers can't
-          ;; really be assigned to it, among other quirks. We create a *real*
-          ;; main workspace to fill this role.
-          (unless (persp-get-by-name +workspaces-main)
-            (persp-add-new +workspaces-main))
-          ;; Switch to it if we aren't auto-loading the last session
-          (when (and (string= (safe-persp-name (get-current-persp)) persp-nil-name)
-                     (= persp-auto-resume-time -1))
-            (persp-frame-switch +workspaces-main frame)
-            ;; We want to know where we are in every new daemon frame
-            (when (daemonp)
-              (run-at-time 0.1 nil #'+workspace/display))
-            ;; Fix #319: the warnings buffer gets swallowed by creating
-            ;; `+workspaces-main', so we display it manually, if it exists.
-            (when-let* ((warnings (get-buffer "*Warnings*")))
-              (save-excursion
-                (display-buffer-in-side-window
-                 warnings '((window-height . shrink-window-if-larger-than-buffer))))))))))
+      (persp-mode +1)
+      (unless noninteractive
+        (let (persp-before-switch-functions persp-activated-functions)
+          (with-selected-frame frame
+            ;; The default perspective persp-mode creates (`persp-nil-name') is
+            ;; special and doesn't represent a real persp object, so buffers can't
+            ;; really be assigned to it, among other quirks. We create a *real*
+            ;; main workspace to fill this role.
+            (unless (persp-get-by-name +workspaces-main)
+              (persp-add-new +workspaces-main))
+            ;; Switch to it if we aren't auto-loading the last session
+            (when (and (string= (safe-persp-name (get-current-persp)) persp-nil-name)
+                       (= persp-auto-resume-time -1))
+              (persp-frame-switch +workspaces-main frame)
+              ;; We want to know where we are in every new daemon frame
+              (when (daemonp)
+                (run-at-time 0.1 nil #'+workspace/display))
+              ;; Fix #319: the warnings buffer gets swallowed by creating
+              ;; `+workspaces-main', so we display it manually, if it exists.
+              (when-let* ((warnings (get-buffer "*Warnings*")))
+                (save-excursion
+                  (display-buffer-in-side-window
+                   warnings '((window-height . shrink-window-if-larger-than-buffer)))))))))))
 
   (add-hook 'doom-post-init-hook #'+workspaces|init t)
   :config