Issue #16714: use 'raise' exceptions, don't 'throw'.

Patch by Serhiy Storchaka.
diff --git a/Tools/scripts/serve.py b/Tools/scripts/serve.py
index 50061d5..399da1a 100755
--- a/Tools/scripts/serve.py
+++ b/Tools/scripts/serve.py
@@ -2,7 +2,7 @@
 '''
 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
+Mime types are guessed from the file names, 404 errors are raised
 if the file is not found. Used for the make serve target in Doc.
 '''
 import sys