move GEP-1731 from implementable to experimental

remove duplicate index entry

Author: mikemorris

geps/gep-1731/index.md

@@ -1,7 +1,7 @@
 # GEP-1731: HTTPRoute Retries
 
 * Issue: [#1731](https://github.com/kubernetes-sigs/gateway-api/issues/1731)
-* Status: Implementable
+* Status: Experimental
 
 (See status definitions [here](/geps/overview/#gep-states).)
 

geps/gep-1731/metadata.yaml

@@ -2,7 +2,7 @@ apiVersion: internal.gateway.networking.k8s.io/v1alpha1
 kind: GEPDetails
 number: 1731
 name: HTTPRoute Retries
-status: Implementable
+status: Experimental
 # Any authors who contribute to the GEP in any way should be listed here using
 # their Github handle.
 authors:

mkdocs.yml

@@ -125,11 +125,10 @@ nav:
       - geps/gep-2649/index.md
     - Implementable:
       - geps/gep-995/index.md
-      - geps/gep-1731/index.md
       - geps/gep-3155/index.md
-      - geps/gep-1731/index.md
     - Experimental:
       - geps/gep-1619/index.md
+      - geps/gep-1731/index.md
       - geps/gep-1748/index.md
       - geps/gep-1762/index.md
       - geps/gep-1897/index.md