Make ^NOTE in markdown/html files bold

2018/giles/index.html

@@ -424,7 +424,7 @@ installed and don’t know how to do so.</p>
     ./prog sand.txt
 
     ./prog sand.alt.txt</code></pre>
-<p>NOTE: these invocations will take quite some time to finish.</p>
+<p><strong>NOTE</strong>: these invocations will take quite some time to finish.</p>
 <h2 id="judges-remarks">Judges’ remarks:</h2>
 <p>Can you explain the behavior of the program when <a href="ioccc.txt">ioccc.txt</a> is given
 to it as input?</p>