Add some notes about Tools/scripts/serve.py.
diff --git a/Tools/scripts/serve.py b/Tools/scripts/serve.py
index 09d850a..61de63d 100755
--- a/Tools/scripts/serve.py
+++ b/Tools/scripts/serve.py
@@ -1,4 +1,10 @@
#!/usr/bin/env python
+'''
+Small wsgiref based web server. Takes a path to serve from and an
+optional port number (defaults to 8000), then tries to serve files.
+Mime types are guessed from the file names, 404 errors are thrown
+if the file is not found. Used for the make serve target in Doc.
+'''
import sys
import os
import mimetypes