JQuery isn't needed anymore, so fix documentation about skinning

The JQuery requirement was removed in d921161, but it seems we forgot
to remove the documentation that it was required.

Spotted by Kaiting Chen

docs/confreg/skinning.md

@@ -37,8 +37,7 @@ subdirectory.
 ## Base template <a name="basetemplate"></a>
 
 In the base template, the entire HTML structure should be defined. The
-skin can do anything it wants with HTML, css and javascript. Note that
-some pages rely on JQuery being present, so it should always be included.
+skin can do anything it wants with HTML, css and javascript.
 
 The following blocks should be defined in the base template: