Gateway API docs: GRPCRoute example service field missing "User" to match explanation text

**This is a Bug Report**
**Problem:**
On the Gateway API concepts page, the GRPCRoute example YAML and its explanatory text are inconsistent. The YAML sets:

```yaml
rules:
- matches:
- method:
service: com.example
method: Login
```
but the explanation immediately below it states:

> Since there is only one match specified, only requests for the com.example.User.Login method to svc.example.com will be forwarded.

The service field in the YAML is com.example, which is missing the User service name that the explanation refers to.

**Proposed Solution:**
Update the YAML's service field to include the service name, so it matches the explanation text:

```yaml
rules:
- matches:
- method:
service: com.example.User
method: Login
```

**Page to Update:**
https://kubernetes.io/docs/concepts/services-networking/gateway/

Open the Gateway API concepts page at https://kubernetes.io/docs/concepts/services-networking/gateway/ and locate the GRPCRoute example. Update the YAML service field to match the explanatory text, then verify that the example and explanation consistently describe com.example.User.Login.

Written by the indexing model from the issue text.