docs(server-communication): fix anchor link

closes #1537

public/docs/ts/latest/guide/server-communication.jade

@@ -190,7 +190,7 @@ h2#fetch-data Fetch data with the #[b HeroService]
   We pass the resource URL to `get` and it calls the server which should return heroes.
 .l-sub-section
   :marked
-    It *will* return heroes once we've set up the [in-memory web api](in-mem-web-api)
+    It *will* return heroes once we've set up the [in-memory web api](#in-mem-web-api)
     described in the appendix below.
     Alternatively, we can (temporarily) target a JSON file by changing the endpoint URL:
   +makeExample('server-communication/ts/app/toh/hero.service.ts', 'endpoint-json')(format=".")