/**
* Inserts a user into the database.
*
* Most of the `$userdata` array fields have filters associated with the values. Exceptions are
* 'ID', 'rich_editing', 'syntax_highlighting', 'comment_shortcuts', 'admin_color', 'use_ssl',
* 'user_registered', 'user_activation_key', 'spam', and 'role'. The filters have the prefix
* 'pre_user_' followed by the field name. An example using 'description' would have the filter
* called 'pre_user_description' that can be hooked into.
*
* @since 2.0.0
* @since 3.6.0 The `aim`, `jabber`, and `yim` fields were removed as default user contact
* methods for new installations. See wp_get_user_contact_methods().
* @since 4.7.0 The `locale` field can be passed to `$userdata`.
* @since 5.3.0 The `user_activation_key` field can be passed to `$userdata`.
* @since 5.3.0 The `spam` field can be passed to `$userdata` (Multisite only).
* @since 5.9.0 The `meta_input` field can be passed to `$userdata` to allow addition of user meta data.
*
* @global wpdb $wpdb WordPress database abstraction object.
*
* @param array|object|WP_User $userdata {
* An array, object, or WP_User object of user data arguments.
*
* @type int $ID User ID. If supplied, the user will be updated.
* @type string $user_pass The plain-text user password for new users.
* Hashed password for existing users.
* @type string $user_login The user's login username.
* @type string $user_nicename The URL-friendly user name.
* @type string $user_url The user URL.
* @type string $user_email The user email address.
* @type string $display_name The user's display name.
* Default is the user's username.
* @type string $nickname The user's nickname.
* Default is the user's username.
* @type string $first_name The user's first name. For new users, will be used
* to build the first part of the user's display name
* if `$display_name` is not specified.
* @type string $last_name The user's last name. For new users, will be used
* to build the second part of the user's display name
* if `$display_name` is not specified.
* @type string $description The user's biographical description.
* @type string $rich_editing Whether to enable the rich-editor for the user.
* Accepts 'true' or 'false' as a string literal,
* not boolean. Default 'true'.
* @type string $syntax_highlighting Whether to en
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