Matches text anywhere in the message (case insensitive). For example
<code>Bets open</code> would match 'Bets open' or 'BETS OPEN'.

<p>[help-settings:Highlight_Matching Text Matching Prefixes] can be put in front
    of the match text (anything after the prefix will be interpreted as text):</p>
<ul style='margin-left:30px'>
    <li><code>start:!slot</code> - Message beginning with '!slot'</li>
    <li><code>w:Clip</code> - 'Clip' as a word, so e.g. not 'Clipped'</li>
</ul>
[help-settings:Highlight_Meta_Mat