Add missing thing in thanks file

thanks-for-help.html

@@ -4214,6 +4214,8 @@ files from compiling properly, trying instead to compile already compiled code.<
 <div id="2018">
 <h1 id="the-25th-ioccc"><a href="2018/index.html">2018 - The 25th IOCCC</a></h1>
 </div>
+<p><a href="#cody">Cody</a> added the missing <code>README.md</code> file from the winner archive back to
+the repo.</p>
 <div id="2018_anderson">
 <h2 id="winning-entry-2018anderson">Winning entry: <a href="2018/anderson/index.html">2018/anderson</a></h2>
 <h3 id="winning-entry-source-code-prog.c-24">Winning entry source code: <a href="https://github.com/ioccc-src/temp-test-ioccc/blob/master/2018/anderson//prog.c">prog.c</a></h3>

thanks-for-help.md

@@ -5419,6 +5419,9 @@ He also added the [try.sh](%%REPO_URL%%/2015/yang/try.sh) script.
 # [2018 - The 25th IOCCC](2018/index.html)
 </div>
 
+[Cody](#cody) added the missing `README.md` file from the winner archive back to
+the repo.
+
 
 <div id="2018_anderson">
 ## Winning entry: [2018/anderson](2018/anderson/index.html)