Mention Vim is done with magic

Author: remram44

regex.html

@@ -82,7 +82,7 @@ <h1>Syntax</h1>
 
 <table class="table table-bordered table-striped">
   <thead>
-    <tr><th>What</th><th><a href="http://perldoc.perl.org/perlre.html">Perl</a>/PCRE</th><th><a href="https://docs.python.org/library/re.html">Python's <code>re</code></a></th><th>POSIX (BRE)</th><th>POSIX extended (ERE)</th><th>Vim</th></tr>
+    <tr><th>What</th><th><a href="http://perldoc.perl.org/perlre.html">Perl</a>/PCRE</th><th><a href="https://docs.python.org/library/re.html">Python's <code>re</code></a></th><th>POSIX (BRE)</th><th>POSIX extended (ERE)</th><th>Vim (with <code>:set magic</code>)</th></tr>
   </thead>
   <tbody id="syntax-basics" class="subgroup">
     <tr><th colspan="6">Basics</th></tr>