Change note->environment variable and convert <pre> list to <table>.

    string, a string containing format specifiers or a combination

    of both. The following format specifiers are supported in

    <em>value</em>:</p>

<pre>

%t: The time the request was received in Universal Coordinated Time

    since the epoch (Jan. 1, 1970) measured in microseconds. The

    value is preceded by "t=".

%D:     The time from when the request was received to the time the

        headers are sent on the wire. This is a measure of the

    duration of the request. The value is preceded by "D=".

%{NOTE-NAME}e: The value of the note 'NOTE-NAME' (set via 

    mod_include's set SSI command)

</pre>

<table>

<tr><td>%t: </td> <td>The time the request was received in Universal

Coordinated Time since the epoch (Jan. 1, 1970) measured in

microseconds. The value is preceded by "t=".</td></tr>

<tr><td>%D: </td> <td>The time from when the request was received to

the time the headers are sent on the wire. This is a measure of the

duration of the request. The value is preceded by "D=".</td></tr>

<tr><td>%{FOOBAR}e: The contents of the <a href="../env.html">environment

variable</a> FOOBAR.</td></tr>

</table>

    <p>When the <code>Header</code> directive is used with the

    <code>add</code>, <code>append</code>, or <code>set</code>