refactor: Visual indentation guides

- Switch from highlight-indentation package to highlight-indent-guides.
- Activate visual indentation in a prog-mode hook, rather than doing
  within each individual major mode. It was already done within all
  major modes based on prog-mode anyway.
- Add new siren-display-indetation module and function as a central way
  to enable visual indetation guides. This makes switching the
  underlying package at some point in the future much easier.

modules/editor/siren-display-indentation.el

@@ -0,0 +1,17 @@
+;;; siren-display-indentation.el --- jimeh's Emacs Siren: indent guides setup
+
+;;; Commentary:
+
+;; Setup for rendering indent guides.
+
+;;; Code:
+
+(require 'siren-highlight-indent-guides)
+
+(defun siren-display-indentation (&optional arg)
+  "Activate or deactivate indentation guides.
+Optional ARG is passed directly to mode toggle function."
+  (highlight-indent-guides-mode (or arg t)))
+
+(provide 'siren-display-indentation)
+;;; siren-display-indentation.el ends here

modules/editor/siren-highlight-indent-guides.el

@@ -9,7 +9,19 @@
 (use-package highlight-indent-guides
   :defer t
   :commands highlight-indent-guides-mode
-  :diminish highlight-indent-guides-mode)
+  :diminish highlight-indent-guides-mode
+
+  :hook
+  (prog-mode . highlight-indent-guides-mode)
+
+  :custom
+  (highlight-indent-guides-auto-even-face-perc 3)
+  (highlight-indent-guides-auto-odd-face-perc 2.5)
+  (highlight-indent-guides-auto-top-even-face-perc 12)
+  (highlight-indent-guides-auto-top-odd-face-perc 10)
+  (highlight-indent-guides-character ?\u2502)
+  (highlight-indent-guides-method 'column)
+  (highlight-indent-guides-responsive 'top))
 
 (provide 'siren-highlight-indent-guides)
 ;;; siren-highlight-indent-guides.el ends here

modules/editor/siren-highlight-indentation.el

@@ -9,7 +9,10 @@
 (use-package highlight-indentation
   :defer t
   :diminish (highlight-indentation-mode
-             highlight-indentation-current-column-mode))
+             highlight-indentation-current-column-mode)
+
+  :hook
+  (prog-mode . highlight-indent-guides-mode))
 
 (provide 'siren-highlight-indentation)
 ;;; siren-highlight-indentation.el ends here