[PHP 8.4] PCRE - PCRE2-v10.44 updates (#4078)

* [PHP 8.4] PCRE: Add `/r` modifier

* [PHP 8.4] PCRE: Add PCRE2-v10.44 quantifier changes

Author: Ayesh

reference/pcre/pattern.modifiers.xml

@@ -187,6 +187,22 @@
        </simpara>
       </listitem>
      </varlistentry>
+     <varlistentry>
+      <term><emphasis>r</emphasis> (<literal>PCRE2_EXTRA_CASELESS_RESTRICT</literal>)</term>
+      <listitem>
+       <simpara>
+        When <emphasis>u</emphasis> (<literal>PCRE_UTF8</literal>) and <emphasis>i</emphasis> (<literal>PCRE_CASELESS</literal>)
+        are in effect, this modifier prevents matching across ASCII and non-ASCII characters.
+       </simpara>
+       <simpara>
+        For example, <code>preg_match('/\x{212A}/iu', "K")</code> matches the Kelvin sign <literal>K</literal> (U+212A).
+        When <emphasis>u</emphasis> is used (<code>preg_match('/\x{212A}/iur', "K")</code>), it does not match.
+       </simpara>
+       <simpara>
+        Available as of PHP 8.4.0.
+       </simpara>
+      </listitem>
+     </varlistentry>
     </variablelist>
    </blockquote>
   </para>

reference/pcre/pattern.syntax.xml

@@ -1573,12 +1573,23 @@
 
    <literal>\d{8}</literal>
 
-   matches exactly 8 digits. An opening curly bracket that
+   matches exactly 8 digits.
+
+  </para>
+  <simpara>
+   Prior to PHP 8.4.0, an opening curly bracket that
    appears in a position where a quantifier is not allowed, or
    one that does not match the syntax of a quantifier, is taken
-   as a literal character. For example, {,6} is not a quantifier,
-   but a literal string of four characters.
-  </para>
+   as a literal character. For example, <literal>{,6}</literal>
+   is not a quantifier, but a literal string of four characters.
+
+   As of PHP 8.4.0, the PCRE extension is bundled with PCRE2 version 10.44,
+   which allows patterns such as <literal>\d{,8}</literal> and they are
+   interpreted as <literal>\d{0,8}</literal>.
+
+   Further, as of PHP 8.4.0, space characters around quantifiers such as
+   <literal>\d{0 , 8}</literal> and <literal>\d{ 0 , 8 }</literal> are allowed.
+  </simpara>
   <para>
    The quantifier {0} is permitted, causing the expression to
    behave as if the previous item and the quantifier were not