update other entry HTML files

Ran `make gen_other_html` to perform the above.

2020/endoh2/spoiler/spoiler.html

@@ -147,6 +147,8 @@ coded so that it does not require any <code>math.h</code> functions; you don’t
 <code>-lm</code> to <code>cc</code>.</p>
 <p><a href="tmpl.txt">tmpl.txt</a> is a template for the program. <a href="gen.rb">gen.rb</a> composes
 the all items and generates <a href="prog.c">prog.c</a>.</p>
+<hr style="width:10%;text-align:left;margin-left:0">
+<p>Jump to: <a href="#">top</a></p>
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