fix internal links in entry index.html from 1984 thru 2012

1991/dds/README.md

@@ -23,7 +23,7 @@ The author suggests trying:
 ```
 
 Notice that a file `a.c` has been generated.  Can you tell how `a.c` was
-produced?  How does `a.c` relate to [LANDER.BAS](LANDER.BAS)?
+produced?  How does `a.c` relate to [LANDER.BAS](%%REPO_URL%%/1991/ddsLANDER.BAS)?
 
 What happens if you give the program a C program like itself? Try:
 

1991/dds/index.html

@@ -162,7 +162,7 @@ Location: <a href="../../location.html#GR">GR</a> - <em>Hellenic Republic</em> (
 <pre><code>    ./dds LANDER.BAS
     ./a.out</code></pre>
 <p>Notice that a file <code>a.c</code> has been generated. Can you tell how <code>a.c</code> was
-produced? How does <code>a.c</code> relate to <a href="LANDER.BAS">LANDER.BAS</a>?</p>
+produced? How does <code>a.c</code> relate to <a href="https://github.com/ioccc-src/temp-test-ioccc/blob/master/1991/ddsLANDER.BAS">LANDER.BAS</a>?</p>
 <p>What happens if you give the program a C program like itself? Try:</p>
 <pre><code>    ./dds dds.c</code></pre>
 <p>You’ll get errors yes but what does the generated file look like? What about