Add meow-next-thing-include-syntax option.

meow-command.el

@@ -885,7 +885,12 @@ those in INCLUDE-SYNTAX."
 If N is negative, select to the beginning of the previous Nth thing instead."
   (unless (equal type (cdr (meow--selection-type)))
     (meow--cancel-selection))
-  (unless include-syntax (setq include-syntax "'w_ "))
+  (unless include-syntax
+    (setq include-syntax
+          (let ((thing-include-syntax (alist-get thing meow-next-thing-include-syntax)))
+            (if (> n 0)
+                (car thing-include-syntax)
+              (cadr thing-include-syntax)))))
   (let* ((expand (equal (cons 'expand type) (meow--selection-type)))
          (_ (when expand
               (if (< n 0) (meow--direction-backward)
@@ -946,15 +951,15 @@ To select continuous symbols, use following approaches:
 A non-expandable word selection will be created.
 This command works similar to `meow-next-word'."
   (interactive "p")
-  (meow-next-thing meow-word-thing 'word (- n) "_w "))
+  (meow-next-thing meow-word-thing 'word (- n)))
 
 (defun meow-back-symbol (n)
   "Select to the beginning the previous Nth symbol.
 
 A non-expandable word selection will be created.
 This command works similar to `meow-next-symbol'."
   (interactive "p")
-  (meow-next-thing meow-symbol-thing 'symbol (- n) "_w "))
+  (meow-next-thing meow-symbol-thing 'symbol (- n)))
 
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 ;;; LINE SELECTION

meow-var.el

@@ -98,6 +98,16 @@ This will affect how selection is displayed."
   :group 'meow
   :type 'number)
 
+(defcustom meow-next-thing-include-syntax
+  '((word " _w" " _w")
+    (symbol " _w" " _w"))
+  "The syntax to include selecting with meow-next-THING.
+
+Each item is a (THING FORWARD_SYNTAX_TO_INCLUDE BACKWARD-SYNTAX_TO_INCLUDE)."
+  :group 'meow
+  :type '(list :key-type (symbol :tag "Thing")
+               :value-type (list string)))
+
 (defcustom meow-expand-hint-counts
   '((word . 30)
     (line . 30)