Somewhat improve the sectioning.

scribblings/networks.scrbl

@@ -62,6 +62,8 @@ their domains.
 
 }
 
+@section{Networks}
+
 @defstruct*[network ([functions (VariableMapping (UpdateFunction a))]
 		     [domains (DomainMapping a)])]{
 
@@ -91,8 +93,6 @@ The type of the instances of @racket[Network].
                'b '(#f #t)))
 ]}
 
-@section{Constructing networks}
-
 @defproc[(make-same-domains [vars (Listof Variable)]
 			    [domain (Domain a)])
 			    (DomainMapping a)]{