feat(editor): add custom yank-indent package

When yank-indent-mode is enabled, yanked (pasted) text is indented based
on the indent rules of the current major mode. It has a
global-yank-indent-mode too which by default excludes a long list of
known indentation sensitive modes with which this approach does not work
very well.

It is based on some random hacky snippets elisp I've been using for over
a decade. Said snippets are themselves based on some random snippets I
found online, and since morphed into the weird monster they had become.

modules/editor/siren-yank-indent.el

@@ -0,0 +1,17 @@
+;;; siren-yank-indent.el --- jimeh's Emacs Siren: yank-indent configuration.
+
+;;; Commentary:
+
+;; Basic configuration for yank-indent.
+
+;;; Code:
+
+(use-package yank-indent
+  :straight (:type built-in) ;; from vendor directory
+  :demand
+
+  :config
+  (global-yank-indent-mode t))
+
+(provide 'siren-yank-indent)
+;;; siren-yank-indent.el ends here

modules/languages/siren-makefile.el

@@ -21,10 +21,7 @@
   :preface
   (defun siren-makefile-mode-setup ()
     (siren-display-indentation -1)
-    (setq-local tab-width 4))
-
-  :init
-  (add-to-list 'siren-indent-sensitive-modes 'makefile-mode))
+    (setq-local tab-width 4)))
 
 (provide 'siren-makefile)
 ;;; siren-makefile.el ends here