clarify IOCCC subject line requirements

contact.html

@@ -515,6 +515,7 @@ for more information on Mastodon.</p>
 <p>You <strong>MUST</strong> include the following two words (separated by a space) in the subject of your email, otherwise the email will be rejected:</p>
 <pre><code>    IOCCC YYYY</code></pre>
 <p><strong>IMPORTANT:</strong> The <em>YYYY</em> in the above email address <strong>MUST</strong> be changed to the current 4 digit year!</p>
+<p><strong>IMPORTANT:</strong> Do <strong>NOT</strong> immediately proceed nor follow the two words with punctuation. For example, neither <code>IOCCC 2025.</code> <strong>NOR</strong> <code>Re:IOCCC 2025</code> will work in the subject line because there are non-whitespace characters next to the 2 words! Instead use <code>IOCCC 2025 question.</code> or <code>Re: IOCCC 2025</code> or just <code>IOCCC 2025</code> on the subject line.</p>
 <hr style="width:10%;text-align:left;margin-left:0">
 <p>Jump to: <a href="#">top</a></p>
 <!--

contact.md

@@ -82,6 +82,7 @@ You **MUST** include the following two words (separated by a space) in the subje
 
 **IMPORTANT:** The _YYYY_ in the above email address **MUST** be changed to the current 4 digit year!
 
+**IMPORTANT:** Do **NOT** immediately proceed nor follow the two words with punctuation.  For example, neither `IOCCC 2025.` **NOR** `Re:IOCCC 2025` will work in the subject line because there are non-whitespace characters next to the 2 words!  Instead use `IOCCC 2025 question.` or `Re: IOCCC 2025` or just `IOCCC 2025` on the subject line.
 
 <hr style="width:10%;text-align:left;margin-left:0">
 

sitemap.xml

@@ -15434,11 +15434,11 @@
 </url>
 <url>
     <loc>https://www.ioccc.org/contact.html</loc>
-    <lastmod>2025-07-26T18:35:04+00:00</lastmod>
+    <lastmod>2025-07-29T04:52:21+00:00</lastmod>
 </url>
 <url>
     <loc>https://www.ioccc.org/contact.md</loc>
-    <lastmod>2025-07-26T09:01:09+00:00</lastmod>
+    <lastmod>2025-07-29T04:52:16+00:00</lastmod>
 </url>
 <url>
     <loc>https://www.ioccc.org/faq.html</loc>