Clarify some details of using bracket-style delimiters in regular expression patterns

Patch suggested by Brandon Kelly (brandon@pixelandtonic.com)

git-svn-id: https://svn.php.net/repository/phpdoc/en/trunk@334410 c90b9560-bf6c-de11-be94-00142212c4b1

reference/pcre/pattern.syntax.xml

@@ -44,20 +44,7 @@
 #^[^0-9]$#
 +php+
 %[a-zA-Z0-9_-]%
-]]>
-    </programlisting>
-   </informalexample>
-  </para>
-  <para>
-   In addition to the aforementioned delimiters, it is also possible to use
-   bracket style delimiters where the opening and closing brackets are the
-   starting and ending delimiter, respectively.
-   <informalexample>
-    <programlisting>
-<![CDATA[
-{this is a pattern}
-(foobar)
-<\d+>
+{\w[\w0-9]*}
 ]]>
     </programlisting>
    </informalexample>
@@ -79,6 +66,26 @@
    for injection into a pattern and its optional second parameter may be used 
    to specify the delimiter to be escaped.
   </para>
+  <para>
+   In addition to the aforementioned delimiters, it is also possible to use
+   bracket style delimiters where the opening and closing brackets are the
+   starting and ending delimiter, respectively. <literal>()</literal>,
+   <literal>{}</literal>, <literal>[]</literal> and <literal>&lt;&gt;</literal>
+   are all valid bracket style delimiter pairs.
+   <informalexample>
+    <programlisting>
+<![CDATA[
+(this [is] a (pattern))
+{this [is] a (pattern)}
+[this [is] a (pattern)]
+<this [is] a (pattern)>
+]]>
+    </programlisting>
+   </informalexample>
+   Bracket style delimiters do not need to be escaped when they are used as meta
+   characters within the pattern, but as with other delimiters they must be
+   escaped when they are used as literal characters.
+  </para>
   <para>
    You may add <link linkend="reference.pcre.pattern.modifiers">pattern
    modifiers</link> after the ending delimiter. The following is an example