Format fixes in html files of 2013

2013/cable3/index.html

@@ -545,7 +545,7 @@ include to the top of the source:</p>
 <p><strong>NOTE</strong>: this has been done in <a href="https://github.com/ioccc-src/temp-test-ioccc/blob/master/2013/cable3/cable3.c">cable3.c</a>.</p>
 <h3 id="usage">Usage</h3>
 <pre><code>    ./cable3 bios-image-file floppy-image-file [harddisk-image-file]</code></pre>
-<p>PLEASE NOTE that under Unices the keyboard must be in raw mode for the emulator
+<p><strong>PLEASE NOTE</strong> that under Unices the keyboard must be in raw mode for the emulator
 to work properly. Therefore the emulator is best run from a shell script that
 looks something like:</p>
 <pre><code>    stty cbreak raw -echo min 0