[gnus] Add bindings for slave/unplugged startup. FLAME ON.

Co-Authored-By: duianto <otnaiud@gmail.com>

CHANGELOG.develop

@@ -1657,6 +1657,15 @@ Other:
   - Added ~g r~ for =gnus-group-get-new-news= (thanks to Matthew Leach)
   - Added ~O~ prefix in evil state for =gnus-group-group-map=
     (thanks to Matthew Leach)
+  - Added *unplugged* and *slave* variants. These are for offline usage and
+    having multiple gnus running, respectively.
+    - ~SPC a g g~ gnus (normal). Not slave, plugged.
+    - ~SPC a g o~ slave & unplugged.
+    - ~SPC a g u~ unplugged (but not slave).
+    - ~SPC a g s~ gnus slave (but plugged).
+      (thanks to Spenser Truex)
+  - Added message mode insert binding: ~SPC m i F~ for FLAME ON, following
+    [[https://tools.ietf.org/html/rfc1855#page-4][RFC 1855]] (thanks to Spenser Truex)
 - Improvements:
   - Added a =@gnus= perspective (~SPC l o g~) to the layouts transient state
     (thanks to Matthew Leach)

layers/+email/gnus/packages.el

@@ -30,7 +30,16 @@
     :defer t
     :commands gnus
     :init
-    (spacemacs/set-leader-keys "ag" 'gnus)
+    (progn (spacemacs/declare-prefix "ag" "gnus" "Gnus newsreader")
+           (spacemacs/set-leader-keys
+             "agg" 'gnus
+             "ags" 'gnus-slave
+             "agu" 'gnus-unplugged
+             "ago" 'gnus-slave-unplugged)
+           (spacemacs/declare-prefix-for-mode 'message-mode "mi" "insert")
+           (spacemacs/set-leader-keys-for-major-mode 'message-mode
+             ;; RFC 1855
+             "miF" 'flame-on))
     :config
     (progn
       ;; No primary server
@@ -71,6 +80,14 @@
 
       (require 'browse-url)
       (require 'nnrss)
+      (defun spacemacs/gnus-flame-on ()
+        "Most important email function, for RFC1855 compliance."
+        ;; https://tools.ietf.org/html/rfc1855
+        (interactive)
+        (insert "FLAME ON:\n")
+        (insert "FLAME OFF\n")
+        (forward-line -2)
+        (end-of-line))
       (defun spacemacs/browse-nnrss-url (arg)
         "Open RSS Article directy in the browser"
         (interactive "p")