fix broken markdown local links in 2015/endoh2/README.md

Ran `bin/readme2index.sh -v 1 2015/endoh2` to perform the above.

2015/endoh2/README.md

@@ -42,7 +42,7 @@ Where did those underscores come from?  Well [RTFS](http://acronyms.thefreedicti
 ** Read the Freaking Source (polite form)
 ** Read The Freaking Screen (polite form)
 
-If you are still puzzled, look at [prog.c](%%REPO_URL%%/2015/endoh2/Rprog.c) with your favorite text editor.
+If you are still puzzled, look at [prog.c](%%REPO_URL%%/2015/endoh2/prog.c) with your favorite text editor.
 
 
 ## Author's remarks:

2015/endoh2/index.html

@@ -417,7 +417,7 @@ Location: <a href="../../location.html#JP">JP</a> - <em>Japan</em></li>
 <p>Where did those underscores come from? Well <a href="http://acronyms.thefreedictionary.com/RTFS">RTFS</a>!**</p>
 <p>** Read the Freaking Source (polite form)
 ** Read The Freaking Screen (polite form)</p>
-<p>If you are still puzzled, look at <a href="https://github.com/ioccc-src/temp-test-ioccc/blob/master/2015/endoh2/Rprog.c">prog.c</a> with your favorite text editor.</p>
+<p>If you are still puzzled, look at <a href="https://github.com/ioccc-src/temp-test-ioccc/blob/master/2015/endoh2/prog.c">prog.c</a> with your favorite text editor.</p>
 <h2 id="authors-remarks">Author’s remarks:</h2>
 <p><strong>Follow these instructions literally!</strong></p>
 <pre><code>    cat prog.c