Add evil-treat-composed-chars-as-one option

Allows user to disable special handling of composed characters. See the
docstring for more information.

evil-common.el

@@ -3000,13 +3000,14 @@ the positions to be outside of this sequence."
  (when (and (numberp beg) (numberp end))
  (setq beg-out (min beg end))
  (setq end-out (max beg end))
- (let ((comp (find-composition beg-out)))
- ;; find-composition returns (FROM TO VALID-P)
- (when (and (listp comp) (nth 2 comp))
- (setq beg-out (nth 0 comp))))
- (let ((comp (find-composition end-out)))
- (when (and (listp comp) (nth 2 comp))
- (setq end-out (nth 1 comp))))
+ (when evil-treat-composed-chars-as-one
+ (let ((comp (find-composition beg-out)))
+ ;; find-composition returns (FROM TO VALID-P)
+ (when (and (listp comp) (nth 2 comp))
+ (setq beg-out (nth 0 comp))))
+ (let ((comp (find-composition end-out)))
+ (when (and (listp comp) (nth 2 comp))
+ (setq end-out (nth 1 comp)))))
  (append (list beg-out end-out)
  (when (evil-type-p type)
  (list type))

evil-vars.el

@@ -1104,6 +1104,19 @@ without having to introduce new niche functionality.
 Prefer to set `evil-v$-excludes-newline' to non-nil."
  "1.15.0")
 
+(defcustom evil-treat-composed-chars-as-one nil
+ "EXPERIMENTAL. Treat composed characters as single characters.
+
+Composed characters are sequences of characters in the buffer
+that are displayed as a single glyph. This is the device used by
+`prettify-symbols-mode' among others. This option tells evil that
+these sequences of characters should be treated as a single unit
+to, for example, prevent part of the sequence from being deleted
+by an evil command. It alters low-level functionality of evil and
+is considered experimental."
+ :type 'boolean
+ :group 'evil)
+
 (defcustom evil-v$-excludes-newline nil
  "If non-nil, `evil-end-of-line' does not move as far as to include
 the `\n' char at eol. This makes `v$' consistent with `$' used as a