fix many internal links

Fixed a number of internal links that need to
go to the GitHub site.

Ran `make www` to perform the above.

2020/burton/README.md

@@ -80,7 +80,7 @@ transformation occurs.
 
 ### Rule 2-ish:
 
-Exporting the constants `B`,`I`,`T`,`S` to the [Makefile](Makefile) allows the
+Exporting the constants `B`,`I`,`T`,`S` to the [Makefile](%%REPO_URL%%/2020/burton/Makefile) allows the
 code to be compiled for either LE (little-endian) or BE (big-endian)
 machines(!!), so they are truly configuration parameters, not logic.
 

2020/burton/index.html

@@ -412,7 +412,7 @@ result?</p>
 <p>Invoke this with a single non-negative integer less than 256, and a useful
 transformation occurs.</p>
 <h3 id="rule-2-ish">Rule 2-ish:</h3>
-<p>Exporting the constants <code>B</code>,<code>I</code>,<code>T</code>,<code>S</code> to the <a href="Makefile">Makefile</a> allows the
+<p>Exporting the constants <code>B</code>,<code>I</code>,<code>T</code>,<code>S</code> to the <a href="https://github.com/ioccc-src/temp-test-ioccc/blob/master/2020/burton/Makefile">Makefile</a> allows the
 code to be compiled for either LE (little-endian) or BE (big-endian)
 machines(!!), so they are truly configuration parameters, not logic.</p>
 <h3 id="notes">Notes:</h3>