set tentative IOCCC28 dates, update rules and guidelines

We set dates and times for when IOCCC28 will go into pending state,
open state, and judging state.  These dates are subject to change until
the content enters the open state.

Modified both `next/guidelines.md` and `next/rules.md` as per the
IOCCC28 dates and times.

Improve the `next/guidelines.md` and `next/rules.md` text around IOCCC28 dates and times.

We processed the XXX's in markdown files that needed processing.

Fixed a minor typo in `bin/cvt-submission.sh`.

Made some minor formatting improvements to `faq.md`, `next/register.md`,
`next/rules.md`, `next/guidelines.md`, `README.md` and `index.md`.

Updated "Rule 3" in `next/rules.md` in regards to the above.

Updated "Rule 8" in `next/rules.md` in regards to the above.

Changed `faq.md`  version from **28.1.8 2024-12-07**
to **28.2.0 2024-12-28**.

Changed `next/guidelines.md` version from **28.29 2024-12-27**
to **28.30 2024-12-28**.

Changed `next/rules.md` version from **28.14 2024-12-07**
to **28.15 2024-12-28**.

TODO: Review these changes.

next/register.html

@@ -430,7 +430,7 @@
 </div>
 <p>The contest needs to be either <a href="../status.html#pending">pending</a> or <a href="../status.html#open">open</a>
 in order to register for the IOCCC.</p>
-<p>For details see the “<a href="#status_impact">How the contest status impacts registration</a>” section below.</p>
+<p>For details see the “<a href="#status_impact">how the contest status impacts registration</a>” section below.</p>
 <div id="step_b">
 <h2 id="step-b-enter-your-email-address">Step B: Enter your email address</h2>
 </div>
@@ -540,8 +540,8 @@ receive an email message containing your <a href="https://submit.ioccc.org">IOCC
 you may <strong>register for the contest</strong>. Once you are registered <strong>AND</strong>
 the contest is <a href="../status.html#open">open</a>, you will receive an email message containing your very own
 <strong>Username and Initial Password until the contest is <a href="../status.html#open">open</a></strong>. You will need these
-to be able to <a href="submit.html">upload your submissions</a> to the <a href="https://submit.ioccc.org">IOCCC submit
-server</a>.</p>
+to be able to “<strong><a href="submit.html">upload your submissions</a></strong>” to the
+<a href="https://submit.ioccc.org">IOCCC submit server</a>.</p>
 <p>See also the
 FAQ on “<a href="../faq.html#submit">how to upload your submission</a>”
 for more information on the submission process when the IOCCC <a href="../status.html#open">reopens</a>.</p>