Update examples.md to make the test examlpe more generic.

replaced the hardwired path to the python interpreter with the more generic sys.executable that should work on all platforms.

docs/source/examples.md

@@ -17,9 +17,10 @@ Projects can also add the `jupyter-server-proxy` topic to the GitHub repository
 
 If you just want to test if the proxy config is correct you can put the following into `$HOME/.jupyter/jupyter_server_config.py`:
 ```python
+import sys
 c.ServerProxy.servers.update({
     "pythonweb": {
-    "command": ["/usr/local/anaconda/bin/python", "-m", "http.server", "{port}"],
+    "command": [sys.executable, "-m", "http.server", "{port}"],
     "port": 9081,
     "absolute_url": False
     }