Doesn't highlight Rust documentation code examples

[wizard-28]

The code example in the documentation isn't highlighted. I'm using Doom Emacs with the tree-sitter module enabled.

Here's my tree-sitter config:

(global-tree-sitter-mode)
(add-hook 'tree-sitter-after-on-hook #'tree-sitter-hl-mode)
;; HACK: https://github.com/emacs-tree-sitter/elisp-tree-sitter/issues/64
(setq-default spell-fu-faces-include
              '(tree-sitter-hl-face:comment
                tree-sitter-hl-face:doc
                tree-sitter-hl-face:string
                font-lock-comment-face
                font-lock-doc-face
                font-lock-string-face))