Fontify Grimoire code blocks if possible

Fixes #1959.

CHANGELOG.md

@@ -4,6 +4,7 @@
 
 ### New Features
 
+* [#2007](https://github.com/clojure-emacs/cider/pull/2007): Fontify code blocks from `cider-grimoire` if possible.
 * [#1990](https://github.com/clojure-emacs/cider/issues/1990): Add new customation variable `cider-save-files-on-cider-refresh` to allow auto-saving buffers when `cider-refresh` is called.
 * Add new function `cider-load-all-files`, along with menu bar update.
 * Add new customization variable `cider-special-mode-truncate-lines`.

cider-grimoire.el

@@ -35,6 +35,8 @@
 
 (require 'url-vars)
 
+(declare-function markdown-mode "markdown-mode.el")
+
 (defconst cider-grimoire-url "http://conj.io/")
 
 (defconst cider-grimoire-buffer "*cider-grimoire*")
@@ -78,6 +80,11 @@ opposite of what that option dictates."
   (with-current-buffer (cider-popup-buffer cider-grimoire-buffer t)
     (read-only-mode -1)
     (insert content)
+    (when (require 'markdown-mode nil 'noerror)
+      (markdown-mode)
+      (cider-popup-buffer-mode 1)
+      (when (fboundp 'markdown-toggle-fontify-code-blocks-natively)
+        (markdown-toggle-fontify-code-blocks-natively 1)))
     (read-only-mode +1)
     (goto-char (point-min))
     (current-buffer)))