Add documentation to two toggles

Two `SPC h SPC` toggles were missing their documentation:
- Nameless
- Minibuffer System Monitor (the symon package)

Now they match the other entries by showing:
- current state
- name (this was only shown before)
- documentation
- key binding (only minibuffer-system-monitor shows a key binding)

The nameless key binding `SPC m T n` only works in emacs-lisp-mode. It's key
binding might need to be described another way.

layers/+lang/emacs-lisp/packages.el

@@ -211,6 +211,7 @@
         :status nameless-mode
         :on (nameless-mode)
         :off (nameless-mode -1)
+        :documentation "Hide package namespaces in your emacs-lisp code."
         :evil-leader-for-mode (emacs-lisp-mode . "Tn"))
       ;; activate nameless only when in a GUI
       ;; in a terminal nameless triggers all sorts of graphical glitches.

layers/+spacemacs/spacemacs-modeline/packages.el

@@ -190,6 +190,7 @@
             symon-refresh-rate 2)
       (spacemacs|add-toggle minibuffer-system-monitor
         :mode symon-mode
+        :documentation "Tiny graphical system monitor."
         :evil-leader "tms"))))
 
 (defun spacemacs-modeline/init-vim-powerline ()