Docs: Remove `@global` tag for `$wpdb` from `wp-admin/install.php` and `wp-admin/upgrade.php`.

Per the documentation standards, the `@global` tag is meant to list PHP globals used within functions or methods.

The code in question uses the variable in global namespace, but does not explicitly declare it.

Props jayupadhyay01, dswebsme.
Fixes #46602.
Built from https://develop.svn.wordpress.org/trunk@45233


git-svn-id: http://core.svn.wordpress.org/trunk@45042 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-admin/install.php

@@ -229,7 +229,6 @@ if ( is_blog_installed() ) {
  * @global string $wp_version
  * @global string $required_php_version
  * @global string $required_mysql_version
- * @global wpdb   $wpdb
  */
 global $wp_version, $required_php_version, $required_mysql_version;
 

wp-admin/upgrade.php

@@ -40,7 +40,6 @@ if ( 'upgrade_db' === $step ) {
  * @global string $wp_version
  * @global string $required_php_version
  * @global string $required_mysql_version
- * @global wpdb   $wpdb
  */
 global $wp_version, $required_php_version, $required_mysql_version;
 

wp-includes/version.php

@@ -13,7 +13,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '5.2-beta3-45232';
+$wp_version = '5.2-beta3-45233';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.