Fixes for recent commits

The Makefile.example file now has the ALT_OBJ and ALT_TARGET (with a
comment explaining how to use it) and the alt rule (which if the
variables are left empty it will do nothing with 'make alt' or 'make
everything').

The example Makefile now has the everything rule as well, for those who
have an alt target.

Fix links to next/try.sh, next/try.alt.sh and next/Makefile.example in
html files (guidelines/rules/FAQ) to not link to GitHub as they're
supposed to be downloaded.

next/rules.html

@@ -466,7 +466,7 @@ writing by <a href="../contact.html">contacting the judges</a>.</p>
 </div>
 <p>Jump to: <a href="#">top</a></p>
 <p class="leftbar">
-These <a href="rules.html">IOCCC rules</a> are version <strong>28.11 2024-12-01</strong>.
+These <a href="rules.html">IOCCC rules</a> are version <strong>28.12 2024-12-04</strong>.
 </p>
 <p><strong>IMPORTANT</strong>: Be sure to read the <a href="guidelines.html">IOCCC guidelines</a>.</p>
 <p>Jump to: <a href="#">top</a></p>
@@ -905,7 +905,7 @@ those requirements.
 <p class="leftbar">
 The <code>Makefile</code> <strong>MUST</strong> be a <strong>non</strong>-empty file in <strong><a href="https://www.gnu.org/software/make/manual/make.html">GNU
 Makefile</a></strong> form. See the
-<a href="https://github.com/ioccc-src/temp-test-ioccc/blob/master/next/Makefile.example">Makefile.example</a>,
+<a href="Makefile.example">Makefile.example</a>,
 the
 FAQ on “<a href="../faq.html#submission_makefiles">submission Makefile</a>”
 and the
@@ -1092,7 +1092,7 @@ make(1) compatibility the IOCCC
 supports</a> for more details.</p>
 <p class="leftbar">
 You are <strong>ENCOURAGED</strong> to use
-<a href="https://github.com/ioccc-src/temp-test-ioccc/blob/master/next/Makefile.example">Makefile.example</a>,
+<a href="Makefile.example">Makefile.example</a>,
 renamed as <code>Makefile</code> of course, for help in constructing your <code>Makefile</code>.
 </p>
 <p>The target of the Makefile must be called <code>prog</code>. The original