docs: add ingressClassName to explicitly specify which ingress class should handle each resource (#268)

Author: kayx23

docs/en/latest/getting-started/key-authentication.md

@@ -218,6 +218,7 @@ metadata:
   namespace: ingress-apisix
   name: httpbin-external-domain
 spec:
+  ingressClassName: apisix
   externalNodes:
   - type: Domain
     name: httpbin.org

docs/en/latest/getting-started/load-balancing.md

@@ -187,6 +187,7 @@ metadata:
   namespace: ingress-apisix
   name: httpbin-external-domain
 spec:
+  ingressClassName: apisix
   scheme: https
   passHost: node
   externalNodes:
@@ -201,6 +202,7 @@ metadata:
   namespace: ingress-apisix
   name: mockapi7-external-domain
 spec:
+  ingressClassName: apisix
   scheme: https
   passHost: node
   externalNodes:

docs/en/latest/getting-started/rate-limiting.md

@@ -177,6 +177,7 @@ metadata:
   namespace: ingress-apisix
   name: httpbin-external-domain
 spec:
+  ingressClassName: apisix
   externalNodes:
   - type: Domain
     name: httpbin.org

docs/en/latest/reference/example.md

@@ -295,6 +295,7 @@ metadata:
   namespace: ingress-apisix
   name: get-ip
 spec:
+  ingressClassName: apisix
   rules:
   - http:
       paths:
@@ -318,6 +319,7 @@ metadata:
   namespace: ingress-apisix
   name: httpbin-external-domain
 spec:
+  ingressClassName: apisix
   externalNodes:
   - type: Domain
     name: httpbin.org