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.

template/README.md.year

@@ -3,7 +3,7 @@
 
 ## Standard IOCCC stuff
 
-%%XXX%% - put text here - XXX
+XXX - put text here - XXX
 
 View the `index.html` web page for the given winning entry for information on how
 on how to compile it and how to run the winning program.
@@ -19,17 +19,17 @@ The primary website can be found at [www.ioccc.org](https://www.ioccc.org).
 
 ## Remarks on some of the winning entries
 
-%%XXX%% - add text here - XXX
+XXX - add text here - XXX
 
 
-## %%XXX%% - other remarks if needed - XXX
+## XXX - other remarks if needed - XXX
 
-%%XXX%% - add text here if needed - XXX
+XXX - add text here if needed - XXX
 
 
 ## Final Comments
 
-%%XXX%% - add final text here - XXX
+XXX - add final text here - XXX
 
 **IMPORTANT NOTE**: See [contact.html](../contact.html) for up to date contact details
 as well as details on how to provide fixes to any of the entries.