docs: make alt tcp routes an aside

site-src/v1alpha2/guides/tcp.md

@@ -17,12 +17,6 @@ in order to route them to two separate backend `TCPRoutes`, note that the
 {% include 'v1alpha2/basic-tcp.yaml' %}
 ```
 
-As a note to the above example: while it is possible to use metadata to route
-traffic from the `Gateway` to the underlying `TCPRoutes` (see the
-`spec.rules[].matches[]extensionRef` field in the [spec][tcproute]) such as is
-common for [HTTPRoutes][httproute] the most common use case for making these
-routing decisions with `TCPRoutes` is by port.
-
 In the above example we separate the traffic for the two separate backend TCP
 [Services][svc] by using the `sectionName` field in the `parentRefs`:
 
@@ -49,6 +43,15 @@ In this way each `TCPRoute` "attaches" itself to a different port on the
 `Gateway` so that the service `my-foo-service` is taking traffic for port `8080`
 from outside the cluster and `my-bar-service` takes the port `8090` traffic.
 
+## Alternatives: TCP Traffic Routing Using Metadata
+
+While in the above examples we mainly focused on routing by port, it is also
+possible to use metadata to route traffic from the `Gateway` to the underlying
+`TCPRoutes` using `spec.rules[].matches[].extensionRef`.
+
+See the [spec][tcproute] for more details on how to configure alternative logic
+for routing TCP traffic beyond just using ports and selecting `listener` names.
+
 [tcproute]:/v1alpha2/v1alpha2/references/spec/#gateway.networking.k8s.io/v1alpha2.TCPRoute
 [tcp]:https://datatracker.ietf.org/doc/html/rfc793
 [httproute]:/v1alpha2/v1alpha2/references/spec/#gateway.networking.k8s.io/v1alpha2.HTTPRoute