Fix task-list checkbox styling (#10668)

* Fix task-list checkbox styling

The pandoc renderer will append the class "task-list" to the ul element
wrapping a li with one or more check-boxes. This allows us to select for
them, removing their list-style-type property. However, goldmark and the
gfm spec doesn't specify the "task-list" class name, so we can't use
that to fix the issue there.

Signed-off-by: Alexander Scheel <alexander.m.scheel@gmail.com>

* Update to goldmark v1.1.25

This version adds the missing space after a checkbox.

Resolves: #9656

Signed-off-by: Alexander Scheel <alexander.m.scheel@gmail.com>

Co-authored-by: zeripath <art27@cantab.net>

web_src/less/_markdown.less

@@ -192,6 +192,11 @@
         list-style-type: none;
     }
 
+    ul.task-list,
+    ol.task-list {
+        list-style-type: none;
+    }
+
     ul ul,
     ul ol,
     ol ol,