Update compability doc (nginx#1054)

Update compatability doc with Port for ParentRef

Author: sarthyparty

content/ngf/overview/gateway-api-compatibility.md

@@ -146,7 +146,7 @@ See the [controller]({{< ref "/ngf/reference/cli-help.md#controller">}}) command
 **Fields**:
 
 - `spec`
-  - `parentRefs`: Partially supported. Port not supported.
+  - `parentRefs`: Supported.
   - `hostnames`: Supported.
   - `rules`
     - `matches`
@@ -195,7 +195,7 @@ See the [controller]({{< ref "/ngf/reference/cli-help.md#controller">}}) command
 **Fields**:
 
 - `spec`
-  - `parentRefs`: Partially supported. Port not supported.
+  - `parentRefs`: Supported.
   - `hostnames`: Supported.
   - `rules`
     - `matches`
@@ -257,7 +257,7 @@ Fields:
 **Fields**:
 
 - `spec`
-  - `parentRefs`: Partially supported. Port not supported.
+  - `parentRefs`: Supported.
   - `hostnames`: Supported.
   - `rules`
     - `backendRefs`: Partially supported. Only one backend ref allowed.