gnu: emacs-markup-faces: Fix build.

* gnu/packages/emacs-xyz.scm (emacs-markup-faces)[source]: Use GitHub as
upstream, MELPA Stable failed us…
[description]: Appease linter and fix capitalization.

gnu/packages/emacs-xyz.scm

@@ -26305,26 +26305,29 @@ show it; if it's not, we want to hide whatever fold the cursor is in.")
       (license license:gpl2+))))
 
 (define-public emacs-markup-faces
-  (package
-    (name "emacs-markup-faces")
-    (version "1.0.0")
-    (source
-     (origin
-       (method url-fetch)
-       (uri (string-append "https://stable.melpa.org/packages/markup-faces-"
-                           version ".el"))
-       (sha256
-        (base32
-         "124dxbaa25fwxnpwsygpz7pw6da6dnnw7y2lic3jf8rgz7lw4v32"))))
-    (build-system emacs-build-system)
-    (home-page "https://github.com/sensorflo/markup-faces")
-    (synopsis "Collection of Emacs faces for markup language modes")
-    (description "emacs-markup-faces is like font-lock-faces, but tailored for
-markup languages instead programming languages.  The sub group markup-faces-text
-is also intended for 'text viewing modes' such as info or (wo)man.  This gives a
-common look and feel, or let's say theme, across different markup language modes
-and 'text viewing modes' respectively.")
-    (license license:gpl3+)))
+  (let ((commit "98a807ed82473eb41c6a201ed7ef816d6bcd67b0"))
+    (package
+      (name "emacs-markup-faces")
+      (version "1.0.0")
+      (source
+       (origin
+         (method git-fetch)
+         (uri (git-reference
+               (url "https://github.com/sensorflo/markup-faces")
+               (commit commit)))
+         (file-name (git-file-name name version))
+         (sha256
+          (base32
+           "1w6i1m7xdr9cijnmdj35cl99r12vl83qws0qlfhrgvisilshnr27"))))
+      (build-system emacs-build-system)
+      (home-page "https://github.com/sensorflo/markup-faces")
+      (synopsis "Collection of Emacs faces for markup language modes")
+      (description "Markup Faces is like @code{font-lock-faces}, but tailored
+for markup languages instead programming languages.  The sub-group
+@code{markup-faces-text} is also intended for text viewing modes such as Info
+or Woman.  This gives a common look and feel across different markup language
+modes and text viewing modes respectively.")
+      (license license:gpl3+))))
 
 (define-public emacs-adoc-mode
   (package