Bug Report

• Yes, I reviewed the contribution guidelines.
• Yes, more specifically, I reviewed the guidelines on how to write clear bug reports.

Describe the current, buggy behavior

Deleting a constant with concatenated function from wp-config.php with wp config delete deletes more than just that constant.

Describe how other contributors can replicate this bug

• A wp-config.php file with a constant definition concatenating a function, like in my example
• Run wp config delete USER_PATH

<?php

define( 'WP_DEBUG', false );

define( 'USER_PATH', '/var/www/' . get_current_user() );

define( 'THIS_AND', md5( 'that' ) );

if ( isset( $_SERVER['HTTP_X_FORWARDED_PROTO'] ) && 'https' === $_SERVER['HTTP_X_FORWARDED_PROTO'] ) {
	$_SERVER['HTTPS'] = 'on';
}

define( 'DISABLE_WP_CRON', true );

/* That's all, stop editing! Happy publishing. */

Describe what you would expect as the correct outcome

wp-config.php with just USER_PATH constant definition removed.

Let us know what environment you are running this on

OS:	Linux 4.9.184-linuxkit #1 SMP Tue Jul 2 22:58:16 UTC 2019 x86_64
Shell:
PHP binary:	/usr/local/bin/php
PHP version:	7.3.11
php.ini used:	/usr/local/etc/php/php.ini
WP-CLI root dir:	phar://wp-cli.phar/vendor/wp-cli/wp-cli
WP-CLI vendor dir:	phar://wp-cli.phar/vendor
WP_CLI phar path:	/var/www/html
WP-CLI packages dir:
WP-CLI global config:
WP-CLI project config:
WP-CLI version:	2.4.0