processed more of John Dalbec's fix of 2000/dlowe

Added processing of "%%REPO_TOP_URL%%" tokens to `bin/subst.default.sh`.

Updated `find-missing-links.sh` to not falsely report missing links
when a "%%REPO_TOP_URL%%" token is used.

Changed `bin/subst.default.sh` VERSION from "1.3.2 2024-08-05"
to "1.4.0 2025-04-16".

Changed `bin/find-missing-links.sh` VERSION from "1.1.1 2024-04-28"
to "1.2.0 2025-04-16".

Due to a `pandoc(1)` bug fix, `2011/fredriksson/index.html` and
`2012/kang/index.html` were modified.  The bug fix removed extraneous
whitespace that was previously introduced into HTML under certain
situations.  These 2 changes do **NOT** impact the way web browsers
render these pages, however.

Updated sitemap.

Updated tarballs based on entry mods since 2025 March 4
(commit 233e5e90a5 just prior
to the IOCCC28 open).

Tested the above via `make update` on macOS.

status.json

@@ -2,6 +2,6 @@
     "no_comment" : "mandatory comment: because comments were removed from the original JSON spec",
     "IOCCC_status_version" : "1.0 2024-03-09",
     "contest_status" : "pending",
-    "news_update" : "2025-04-16T16:35:11+00:00",
+    "news_update" : "2025-04-16T20:29:15+00:00",
     "status_update" : "2024-12-29T10:01:35+00:00"
 }