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.

1989/index.html

@@ -369,13 +369,13 @@ Look at the winning source and try to figure how it does what it does!
 You may then wish to look at the Author’s remarks for even more details.</p>
 <p>Instructions for use: Run <code>make</code> to compile entries (it is possible that on
 System V or non-Unix systems the Makefile needs to be changed).</p>
-<p>The Makefile for <a href="fubar/indx.html">“Best self modifying program”</a> always uses
+<p>The Makefile for <a href="fubar/index.html">“Best self modifying program”</a> always uses
 the most portable version because there is no loss of functionality in
-using it. In the case of the <a href="tromp/README">“Best game”</a> entry, however, some
+using it. In the case of the <a href="tromp/index.html">“Best game”</a> entry, however, some
 functionality is lost in the portable version and so its Makefile uses
 the original program.</p>
 <p>This year, the <a href="jar.2/index.html">Best of Show</a> was given to the most useful program.</p>
-<p>The <a href="jar.1/indx.html">“Strangest abuse of the rules”</a> award was given this year
+<p>The <a href="jar.1/index.html">“Strangest abuse of the rules”</a> award was given this year
 to stress the fact that starting in 1990, compiling entries must result a
 regular executable file.</p>
 <p><a href="rules.txt">Rules</a> and <a href="../years.html#1989">results</a> were posted to