Mark old data plane proposal as Replaced (nginx#1756)

The old data plane CRD proposal has been replaced with a newer and better proposal for adding native NGINX configuration to the API.

Author: sjberman

docs/proposals/data-plane-config.md

@@ -1,7 +1,7 @@
 # Enhancement Proposal-929: Data Plane Configuration
 
 - Issue: https://github.com/nginxinc/nginx-kubernetes-gateway/issues/929
-- Status: Implementable
+- Status: [Replaced](nginx-extensions.md)
 
 ## Summary
 

docs/proposals/nginx-extensions.md

@@ -1,8 +1,8 @@
 
 # Extensions for NGINX Features
 
-- Issue: #1566
-- Status: Provisional
+- Issue: https://github.com/nginxinc/nginx-gateway-fabric/issues/1566
+- Status: Implementable
 
 ## Summary