gnu: emacs-markdown-mode: Update to 2.4.

* gnu/packages/emacs-xyz.scm (emacs-markdown-mode): Update to 2.4.

gnu/packages/emacs-xyz.scm

@@ -7149,16 +7149,16 @@ provides the following features:
 (define-public emacs-markdown-mode
   (package
     (name "emacs-markdown-mode")
-    (version "2.3")
-    (source (origin
-              (method git-fetch)
-              (uri (git-reference
-                    (url "https://github.com/jrblevin/markdown-mode.git")
-                    (commit (string-append "v" version))))
-              (file-name (git-file-name name version))
-              (sha256
-               (base32
-                "1zm1j4w0f3h01bmmpsv4j4mh6i13nnl8fcqlj2hsa1ncy1lgi8q7"))))
+    (version "2.4")
+    (source
+     (origin
+       (method git-fetch)
+       (uri (git-reference
+             (url "https://github.com/jrblevin/markdown-mode.git")
+             (commit (string-append "v" version))))
+       (file-name (git-file-name name version))
+       (sha256
+        (base32 "1zm1j4w0f3h01bmmpsv4j4mh6i13nnl8fcqlj2hsa1ncy1lgi8q7"))))
     (build-system emacs-build-system)
     (home-page "https://jblevins.org/projects/markdown-mode/")
     (synopsis "Emacs Major mode for Markdown files")