This commit removes the PHP debug adapter in favor of a new version
(0.3.0) of PHP extension.
The name of a debug adapter has been changed from "PHP" to "Xdebug",
which makes this a breaking change in user-configured scenarios
Release Notes:
- debugger: PHP debug adapter is no longer shipped in core Zed editor;
it is now available in PHP extension (starting with version 0.3.0). The
adapter has been renamed from `PHP` to `Xdebug`, which might break your
user-defined debug scenarios.
4693f16759