Use a bad (will-404) URL

Author: bsolomon1124

asyncio-walkthrough/urls.txt

@@ -1,9 +1,8 @@
 https://regex101.com/
-https://docs.python.org/3/index.html
+https://docs.python.org/3/this-url-will-404.html
 https://www.nytimes.com/guides/
 https://www.mediamatters.org/
 https://1.1.1.1/
 https://www.politico.com/tipsheets/morning-money
 https://www.bloomberg.com/markets/economics
-https://wmata.com/
 https://www.ietf.org/rfc/rfc2616.txt