PHP 8 Update for bootstrap.inc

[Dorson]

Updated syntax / variable definition to the PHP 8 version standard.

Makes the bootstrap.inc run on php 8.2

old format was ${VAR} , new PHP8 format is {$VAR}

Simple , one letter change makes it work :-)

[Dorson]

This really solved my issues. Drupal d6lts would not run on my PHP 8.2 version.

The variable syntax change was suggested by PHP 8.2 itself , because it would not execute the code otherwise.

Here is the explanation from the PHP 8.2 documentation :

https://php.watch/versions/8.2/$%7Bvar%7D-string-interpolation-deprecated

Here is the search for all the similar / possilbe bugs of the same type in this repo :

https://github.com/search?q=repo%3Ad6lts%2Fdrupal%20%2F%24%7B%2F&type=code

Hope it helps !