[PR] docs: describe how a wildcard Ingress hostname is matched [apisix-ingress-controller]

["AlinsRan (via GitHub)" <gi...@apache.org>]

AlinsRan opened a new pull request, #2861:
URL: https://github.com/apache/apisix-ingress-controller/pull/2861

   ### Type of change:
   
   - [x] Documentation
   
   ### What this PR does / why we need it:
   
   A wildcard `spec.rules[].host` such as `*.tenant.example.com` also matches `one.two.tenant.example.com`. Users expect it to cover a single label, because that is what the [Kubernetes Ingress documentation](https://kubernetes.io/docs/concepts/services-networking/ingress/#hostname-wildcards) describes, and report the multi-label match as a bug.
   
   The controller passes `rule.Host` to the APISIX `hosts` field unchanged (`internal/adc/translator/ingress.go`, where `NormalizeHosts` only lowercases and de-duplicates), and APISIX matches it as a reversed-domain suffix.
   
   This is not specific to APISIX and is not a regression. v1.8.4 does the same (`pkg/providers/ingress/translation/translator.go`, `route.Host = rule.Host`), and nginx documents the same semantics:
   
   > An asterisk can match several name parts. The name `*.example.org` matches not only `www.example.org` but `www.sub.example.org` as well.
   
   ingress-nginx emits `server_name *.example.org` directly, so it behaves identically. Narrowing the match would be a silent runtime break for anyone relying on it, with no apply-time signal, and would diverge from the most widely deployed Ingress implementation. Documenting it is the better trade.
   
   Gateway API is unaffected either way: `sigs.k8s.io/gateway-api` specifies wildcard hostnames as a multi-label suffix match, so `HTTPRoute` is already correct.
   
   ### Pre-submission checklist:
   
   - [x] Did you explain what problem does this PR solve? Or what new features have been added?
   - [ ] Have you added corresponding test cases?
   - [x] Have you modified the corresponding document?
   - [x] Is this PR backward compatible?


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