update index.html and .entry.json per recent manifest changes

Every index.html file (for entries) was updated as the tarball download
description was changed to 'download entry source' (though I think this
is a mistake as the C file is described as 'entry source' so it's
ambiguous - that might be fixed soon or it mightn't be until some other
changes are made that need a manifest update).

2018/burton2/index.html

@@ -534,7 +534,7 @@ https://creativecommons.org/licenses/by-sa/4.0/</p>
 <li><a href="index.html">index.html</a> - entry home page</li>
 <li><a
 href="https://github.com/ioccc-src/temp-test-ioccc/blob/master/2018/burton2/prog.c">prog.c</a>
-- winning source</li>
+- entry source</li>
 <li><a
 href="https://github.com/ioccc-src/temp-test-ioccc/blob/master/2018/burton2/Makefile">Makefile</a>
 - entry Makefile</li>
@@ -691,7 +691,7 @@ href="https://github.com/ioccc-src/temp-test-ioccc/blob/master/2018/burton2/v7un
 href="https://github.com/ioccc-src/temp-test-ioccc/blob/master/2018/burton2/spotdiff.sh">spotdiff.sh</a>
 - summarize the results of spotcheck</li>
 <li><a href="2018_burton2.tar.bz2">2018_burton2.tar.bz2</a> - download
-winning source</li>
+entry source</li>
 <li><a
 href="https://github.com/ioccc-src/temp-test-ioccc/blob/master/2018/burton2/src.doc.txt">src.doc.txt</a>
 - SPOILER WARNING hints about the source</li>