Remove documentation for deprecated before/before_template/after

Replace detailed docs with a pointer to the hook keyword.

lib/Dancer.pm

@@ -599,21 +599,7 @@ The above would import all keywords as normal, with the exception of C<session>.
 
 =head2 after
 
-Add a hook at the B<after> position:
-
-    after sub {
-        my $response = shift;
-        # do something with response, e.g.:
-        $response->header('X-Beer' => 'Yes please');
-    };
-
-The anonymous function which is given to C<after> will be executed after
-having executed a route, but before the response is returned (so you can modify
-the response here, if you need to)..
-
-You can define multiple after filters, using the C<after> helper as
-many times as you wish; each filter will be executed, in the order you added
-them.
+Deprecated - see the C<after> L<hook|Dancer/hook>.
 
 =head2 any
 
@@ -631,49 +617,11 @@ Or even, a route handler that would match any HTTP methods:
 
 =head2 before
 
-Defines a before filter:
-
-    before sub {
-        # do something with request, vars or params
-    };
-
-The anonymous function given to C<before> will be executed before executing a
-route handler to handle the request.  It will receive a reference to the route
-handler about to be executed as its parameter.
-
-If the function modifies the request's C<path_info> or C<method>, a new
-search for a matching route is performed and the filter is re-executed.
-Considering that this can lead to an infinite loop, this mechanism
-is stopped after 10 times with an exception.
-
-The before filter can set a response with a redirection code (either
-301 or 302): in this case the matched route (if any) will be ignored and the
-redirection will be performed immediately.
-
-You can define multiple before filters, using the C<before> helper as
-many times as you wish; each filter will be executed in the order you added
-them.
+Deprecated - see the C<before> L<hook|Dancer/hook>.
 
 =head2 before_template
 
-Defines a before_template filter:
-
-    before_template sub {
-        my $tokens = shift;
-        # do something with request, vars or params
-        
-        # for example, adding a token to the template
-        $tokens->{token_name} = "some value";
-    };
-
-The anonymous function which is given to C<before_template> will be executed
-before sending data and tokens to the template. Receives a HashRef of the
-tokens that will be inserted into the template.
-
-This filter works as the C<before> and C<after> filter.
-
-Now the preferred way for this is to use C<hook>s (namely, the
-C<before_template> one). Check C<hook> documentation below.
+Deprecated - see the C<before_template> L<hook|Dancer/hook>.
 
 =head2 cookies