Update simulator extension docs and config (#5981)

* add sample simx to targetconfig.json

* add empty testSimulatorExtensions, update simx-sample sha

* update config, docs

docs/extensions/build-your-own.md

@@ -17,3 +17,8 @@ Go to the MakeCode extension documentation and see the [getting started](https:/
 Extensions are also known, and referred to, as _packages_. The term _package_ is currently used in the MakeCode documentation for developing and deploying extensions.
 
 ## ~
+
+
+## See also
+
+[Simulator extensions](./simulator-extensions.md)

targetconfig.json

@@ -465,9 +465,9 @@
             "pythom1234/pxt-oled": { "tags": [ "Lights and Display" ] },
             "softsmyth/lectrify-b4k": { "tags": [ "Robotics" ] },
             "davidnsousa/sonification": { "tags": [ "Software" ] },
-            "eanders-ms/simx-sample": {
+            "microsoft/pxt-simx-sample": {
                 "simx": {
-                    "sha": "6555401f995fac26ebafbaf1f1b1261ae72a05b3",
+                    "sha": "24e0315d3715c2e5ca1acf9947893085459a38e1",
                     "devUrl": "http://localhost:5173"
                 }
             }