improve receiver_creator and k8sobserver docs (#35323)

**Description:** 
This PR includes the `k8s.ingress` type in the list of supported types
and adds a note in `k8sobserver`'s back to the `receiver_creator`'s docs
so as users can find more extensive configuration examples.

**Link to tracking Issue:** <Issue number if applicable> Fixes
#34740

---------

Signed-off-by: ChrsMark <[email protected]>

Author: ChrsMark

extension/observer/k8sobserver/README.md

@@ -73,3 +73,6 @@ All fields are optional.
 | observe_nodes | bool | `false` | Whether to report observer k8s.node endpoints. If `true` and `node` is specified it will only discover node endpoints whose `metadata.name` matches the provided node name. If `true` and `node` isn't specified, it will discover all available node endpoints. Please note that Collector connectivity to nodes is dependent on your cluster configuration and isn't guaranteed.| 
 | observe_services | bool | `false` | Whether to report observer k8s.service endpoints.|
 | observe_ingresses | bool | `false` | Whether to report observer k8s.ingress endpoints.|  
+
+More complete configuration examples on how to use this observer along with the `receiver_creator`,
+can be found at the [Receiver Creator](../../../receiver/receivercreator/README.md)'s documentation.

receiver/receivercreator/README.md

@@ -133,6 +133,12 @@ None
 | k8s.node.name      | \`name\`          |
 | k8s.node.uid       | \`uid\`           |
 
+`type == "k8s.ingress"`
+
+| Resource Attribute | Default           |
+|--------------------|-------------------|
+| k8s.namespace.name | \`namespace\`     |
+
 See `redis/2` in [examples](#examples).
 
 
@@ -149,7 +155,7 @@ Similar to the per-endpoint type `resource_attributes` described above but for i
 
 ## Rule Expressions
 
-Each rule must start with `type == ("pod"|"port"|"hostport"|"container"|"k8s.service"|"k8s.node") &&` such that the rule matches
+Each rule must start with `type == ("pod"|"port"|"hostport"|"container"|"k8s.service"|"k8s.node"|"k8s.ingress") &&` such that the rule matches
 only one endpoint type. Depending on the type of endpoint the rule is
 targeting it will have different variables available.