demo: fix instructions
MODIFY
demo/index.html
demo/index.html
"<a href="https://en.wikipedia.org/wiki/Macguffin">MacGuffin</a>", in this
case a random code which the attacker (below) is trying to guess. Everything
is running inside a single SES RootRealm. The attacker's code (pasted into
-the text box) is evaluated by the defender when the Run button is
+the text box) is evaluated by the defender when the Execute button is
pressed.</p>
<p>The secret consists of a ten-character alphanumeric code (about 52 bits of

demo: fix instructions