chore(website): add wip createMiddleware section

website/docs/safe-action-client/middleware.md

@@ -203,4 +203,8 @@ Note that the second line comes from the default `handleServerErrorLog` function
 
 ## Context extension
 
-Visit the [context extension](/docs/recipes/extend-context) recipe for more information on how to extend context with middleware functions.
+Visit the [context extension](/docs/recipes/extend-context) recipe for more information on how to extend context with middleware functions.
+
+## Create standalone middleware with `createMiddleware`
+
+WIP