Code Modernization: Use correct property in IXR_Message::tag_open().

The `IXR_Message` class declares a property `_currentTag`, which is never assigned or used. It does assign to `currentTag` instead, which outside of that one assignment is never used either.

Since there are various other underscore-prefixed properties declared on the class, including one named `_currentTagContents` which is used in several places, it appears that the declared property is correct and the assignment is a typo.

This commit resolves a notice on PHP 8.2:
{{{
Deprecated: Creation of dynamic property IXR_Message::$currentTag is deprecated
}}}

Follow-up to [1346].

Props bjorsch, kraftbj, jrf, mukesh27, SergeyBiryukov.
See #56790.
Built from https://develop.svn.wordpress.org/trunk@55105


git-svn-id: http://core.svn.wordpress.org/trunk@54638 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/IXR/class-IXR-message.php

@@ -144,7 +144,7 @@ function parse()
     function tag_open($parser, $tag, $attr)
     {
         $this->_currentTagContents = '';
-        $this->currentTag = $tag;
+        $this->_currentTag = $tag;
         switch($tag) {
             case 'methodCall':
             case 'methodResponse':

wp-includes/version.php

@@ -16,7 +16,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '6.2-alpha-55104';
+$wp_version = '6.2-alpha-55105';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.