Update header of guidelines.md and rules.md based on status.json

In a few cases, the error message related to a file or directory
test was corrected.

Changed `bin/gen-sitemap.sh` VERSION from "1.3.6 2024-04-13"
to "1.3.7 2024-04-14".

Changed `bin/gen-year-index.sh` VERSION from "1.0.6 2024-04-13"
to "1.0.7 2024-04-14".

Changed `bin/untar-year.sh` VERSION from "1.0.1 2024-04-13"
to "1.0.2 2024-04-14".

Updated `bin/gen-status.sh` to change the header of `next/guidelines.md`
and `next/rules.md` to match the _contest_status_ in `status.json`.

Moved `make gen_top_html` after `make gen_status` in `make www`
and in `make quick_www` rules in the top Makefile.

Changed `bin/gen-status.sh` VERSION from "1.2.1 2024-04-13"
to "1.3 2024-04-14".

Fixed the DESCRIPTION for `next/guidelines.html`.

Run `make www` to perform the above and test under macOS.

inc/rules.open.hdr

@@ -0,0 +1,21 @@
+<!-- START: this line starts content from: inc/rules.open.hdr -->
+
+# Official IOCCC rules
+
+These rules are **OFFICIAL**.
+
+Unless some significant problem turns up (such as a need to delay
+in when the IOCCC will close, or some major bug is discovered) they
+will remain **OFFICIAL** for this IOCCC.
+
+**SUGGESTION**: Watch both the [IOCCC news](../news.html) and the [IOCCC
+Mastodon](https://fosstodon.org/@ioccc) feed for the latest news
+about any _mentions_ changes.
+
+
+# The IOCCC open for submissions
+
+See the [IOCCC news](news.html) page for possible news about updates to these rules.
+
+<!-- END: the next line ends content from: inc/rules.open.hdr -->
+<!-- This is the last line modified by the tool: bin/gen-status.sh -->