fix broken links in next/rules.html and next/guidelines.html

inc/rules.pending.hdr

@@ -5,7 +5,7 @@
 One might think of them as a **beta** release for the IOCCC
 that is about to open.
 
-**IMPORTANT**: All **tentative** [rules](rules.html) and [guidelines](guidelines.html)
+**IMPORTANT**: All **tentative** [rules](../rules.html) and [guidelines](../guidelines.html)
 are subject to change by the [IOCCC judges](../judges.html) at any time.
 See both the [IOCCC news](../news.html) and the [IOCCC
 Mastodon](https://fosstodon.org/@ioccc) feed as _sometimes_ the