feat(editor): try snap-indent as a replacement for yank-indent

Currently trying via my own fork of snap-indent, which has a PR pending.

modules/editor/siren-snap-indent.el

@@ -0,0 +1,19 @@
+;;; siren-snap-indent.el --- jimeh's Emacs Siren: snap-indent configuration.
+
+;;; Commentary:
+
+;; Basic configuration for snap-indent.
+
+;;; Code:
+
+(use-package snap-indent
+  :hook
+  (prog-mode . snap-indent-mode)
+  (tex-mode . snap-indent-mode)
+
+  :custom
+  (snap-indent-yank-threshold 10000)
+  (snap-indent-yank-skip-indent-with-prefix-arg t))
+
+(provide 'siren-snap-indent)
+;;; siren-snap-indent.el ends here