feat(text-editing): Safer case change keybindings (C-x C-u, C-x C-l)

By default when region is not active, both `downcase-region` (C-x C-l)
and `upcase-region` (C-x C-u) will operate on surrounding text in
different ways depending on major-mode. This has caught me off guard a
few times.

So let's replace them with safer `downcase-region-only` and
`upcase-region-only` functions which ONLY perform changes when the
region is active. And obviously changes are only applied to the text
within the region.

core/siren-core-modules.el

@@ -88,6 +88,7 @@
 (require 'siren-move-dup)
 (require 'siren-multiple-cursors)
 (require 'siren-randomize-region)
+(require 'siren-safe-change-case)
 (require 'siren-smart-shift)
 (require 'siren-smartparens)
 (require 'siren-sort-symbols)

modules/text-editing/siren-safe-change-case.el

@@ -0,0 +1,32 @@
+;;; siren-safe-change-case.el --- jimeh's Emacs Siren: change-case
+
+;;; Commentary:
+
+;; Set strict/safer case changing functions to C-x C-u and C-x C-l which ONLY
+;; perform case modifications when region is active.
+
+;;; Code:
+
+(defun downcase-region-only (beg end &rest args)
+  "Only downcase if region (BEG END) is active.
+
+Avoids accidental downcase when region is not active.  Passes all
+additional ARGS passed along to `downcase-region'."
+  (interactive "r")
+  (when (region-active-p)
+    (apply #'downcase-region beg end args)))
+
+(defun upcase-region-only (beg end &rest args)
+  "Only upcase if region (BEG END) is active.
+
+Avoids accidental upcase when region is not active.  Passes all
+additional ARGS passed along to `upcase-region'."
+  (interactive "r")
+  (when (region-active-p)
+    (apply #'upcase-region beg end args)))
+
+(global-set-key (kbd "C-x C-l") 'downcase-region-only)
+(global-set-key (kbd "C-x C-u") 'upcase-region-only)
+
+(provide 'siren-safe-change-case)
+;;; siren-safe-change-case.el ends here