feat: display box styles while matching parens

Remove underlines, and display as VSCode

lisp/init-highlight.el

@@ -43,7 +43,11 @@
 ;; Highlight matching parens
 (use-package paren
   :ensure nil
-  :custom-face (show-paren-match ((t (:underline t))))
+  :custom-face
+  (show-paren-match ((((class color) (background light))
+                      (:box (:line-width (-1 . -1) :color "gray70")))
+                     (((class color) (background dark))
+                      (:box (:line-width (-1 . -1) :color "gray50")))))
   :hook (after-init . show-paren-mode)
   :init (setq show-paren-when-point-inside-paren t
               show-paren-when-point-in-periphery t)