Update AST download link(s)

[mdeweerd]

Phan suggested to get AST from https://windows.php.net/downloads/pecl/releases/ast/1.0.15/php_ast-1.0.15-8.0-ts-vc15-x64.zip
but it is https://windows.php.net/downloads/pecl/releases/ast/1.0.15/php_ast-1.0.15-8.0-ts-vs16-x64.zip .

I suppose that the rules for generating the URL need an update.

On a minor not, the script also indicated:

To install php-ast, add php_ast.dll from the zip to 'C:/wamp/bin/php/php8.0.14/ext/',
Then, enable php-ast by adding the following lines to your php.ini file at 'C:\wamp\bin\php\php8.0.14\php.ini'

While the path to php.ini has backslashes, the path to where the DLL needs to be installed did not.

Thanks for having this hint at runtime!