docs(middleware): drop obsolete dev URL redirect

Signed-off-by: Piotr Mlocek <pmlocek@nvidia.com>

Author: pimlock

fern/docs.yml

@@ -72,8 +72,6 @@ redirects:
     destination: "/openshell/latest/about/run-an-agent"
   - source: "/openshell/dev/about/supported-agents"
     destination: "/openshell/dev/about/run-an-agent"
-  - source: "/openshell/dev/extensibility/middleware"
-    destination: "/openshell/dev/extensibility/supervisor-middleware"
   - source: "/openshell/latest/get-started/quickstart"
     destination: "/openshell/latest/about/run-an-agent"
   - source: "/openshell/dev/get-started/quickstart"