change test files that do not end in .txt to view via GitHub

1988/isaak/.entry.json

@@ -46,7 +46,7 @@
 	    "inventory_order" : 180,
 	    "OK_to_edit" : true,
 	    "display_as" : "xxencode",
-	    "display_via_github" : false,
+	    "display_via_github" : true,
 	    "entry_text" : "uuencoded sample output"
 	},
 	{

1988/isaak/index.html

@@ -208,7 +208,7 @@ file: isaak.encode. To read this file do.</p>
 <li><a href="https://github.com/ioccc-src/temp-test-ioccc/blob/master/1988/isaak/Makefile">Makefile</a> - entry Makefile</li>
 <li><a href="https://github.com/ioccc-src/temp-test-ioccc/blob/master/1988/isaak/isaak.alt.c">isaak.alt.c</a> - alternative source</li>
 <li><a href="https://github.com/ioccc-src/temp-test-ioccc/blob/master/1988/isaak/isaak.orig.c">isaak.orig.c</a> - original source</li>
-<li><a href="isaak.encode">isaak.encode</a> - uuencoded sample output</li>
+<li><a href="https://github.com/ioccc-src/temp-test-ioccc/blob/master/1988/isaak/isaak.encode">isaak.encode</a> - uuencoded sample output</li>
 </ul>
 <h2 id="secondary-files">Secondary files</h2>
 <ul>