feat(navigation): make helm take up full frame

Further tweaks to helm appearance, now simply take up the full frame
with it's completion UI. When follow mode is enabled, have preview
appear in bottom half of the window.

modules/navigation/siren-helm.el

@@ -43,11 +43,12 @@
   (helm-display-header-line t)
   (helm-echo-input-in-header-line t)
   (helm-file-name-case-fold-search 'smart)
-  (helm-follow-mode-persistent t)
-  (helm-full-frame nil)
+  (helm-follow-mode-persistent nil)
+  (helm-full-frame t)
   (helm-show-completion-display-function 'helm-display-buffer-in-own-frame)
-  (helm-split-window-default-side 'below)
+  (helm-split-window-default-side 'above)
   (helm-split-window-inside-p nil)
+  (helm-use-undecorated-frame-option t)
 
   :init
   (defvar siren-helm--did-hide-neotree nil)

themes/siren-doom-themes-overrides-theme.el

@@ -123,6 +123,9 @@
  `(orderless-match-face-3 ((t ( :foreground ,(doom-blend 'magenta 'red 0.7) ))))
 
  ;; helm
+ `(helm-selection ((t ( :inherit 'bold
+                        :background ,(doom-blend 'violet 'bg 0.2)
+                        :extend t ))))
  `(helm-posframe-border ((t ( :background ,(doom-color 'dark-blue) )))))
 
 (custom-theme-set-variables