website: Fix missing HTML document type declaration (see bug #24981)

* haunt.scm (site): Add doctype declaration.
* www/news.scm (base-layout): Ditto.

website/haunt.scm

@@ -74,7 +74,7 @@
       #:builders
       `(,(lambda (site posts)                     ;the main page
            (with-url-parameters
-            (make-page "guix.html" (main-page site posts)
+            (make-page "guix.html" `((doctype "html") ,(main-page site posts))
                        sxml->html)))
         ,@(filter-map (match-lambda
                         (("guix.html" _)          ;handled above
@@ -82,7 +82,9 @@
                         ((file-name contents)
                          (lambda (site posts)
                            (with-url-parameters
-                            (make-page file-name (contents) sxml->html)))))
+                            (make-page file-name
+				       `((doctype "html") ,(contents))
+				       sxml->html)))))
                       %web-pages)
         ,(blog #:theme (parameterized-theme %news-haunt-theme)
                #:prefix "news")

website/www/news.scm

@@ -56,17 +56,18 @@
                 posts))))
 
 (define (base-layout body)
-  `(html (@ (lang "en"))
-	 ,(html-page-header "News" #:css "news.css")
+  `((doctype "html")
+    (html (@ (lang "en"))
+	  ,(html-page-header "News" #:css "news.css")
 
-	 (body
-	  ,(html-page-description)
-	  ,(html-page-links)
+	  (body
+	   ,(html-page-description)
+	   ,(html-page-links)
 
-	  (div (@ (id "content-box"))
-               (article ,body))
+	   (div (@ (id "content-box"))
+		(article ,body))
 
-	  ,(html-page-footer))))
+	   ,(html-page-footer)))))
 
 (define %news-haunt-theme
   ;; Theme for the rendering of the news pages.