Deprecate twitter

We further deprecate the use of twitter.

In cases such as historic guidelines and rules, we add
a note about using Mastodon.

In cases where a tweet URL was used, we replace with
an Internet Archive link because twitter has announced
that accounts that are not used for a period of time
will be deleted.

We add a few missing deprecated_twitter information
to the author.numbers and author.cvs files.

We remove references to twitter handles (after making
sure that both author.numbers and author.cvs has the
deprecated_twitter information).  When the "_README.md_"
files have their header information generated by
a tool, such deprecated_twitter data will not be present.

2013/cable1/README.md

@@ -71,6 +71,17 @@ A PC guy as expected.  What about that other Steve?
 Humm .. maybe there is a hidden reason he is leaving the late Micro$oft? :-)
 Why late?  See [this tweet](https://twitter.com/landonnoll/status/401582967123742720).
 
+-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
+An important 2023 update to this historic note:
+
+The IOCCC no longer uses twitter.  Today the IOCCC uses Mastodon.
+For more information and to see our IOCCC Mastodon posts, see:
+
+    https://fosstodon.org/@ioccc
+
+End of important 2023 update to this historic note.
+-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
+
 So how does a one line C source know so much?  Hint: it doesn't.
 
 ## Author's remarks: