Enable rainbow-delimiters-mode in sh-mode

modules/lang/sh/config.el

@@ -39,6 +39,8 @@
                (1 'sh-quoted-exec prepend))
               (,(regexp-opt +sh-builtin-keywords 'words)
                (0 'font-lock-type-face append))))
+  ;; 4. Fontify delimiters by depth
+  (add-hook 'sh-mode-hook #'rainbow-delimiters-mode)
 
   ;; autoclose backticks
   (sp-local-pair 'sh-mode "`" nil :unless '(sp-point-before-word-p sp-point-before-same-p))