Using `php_error_docref()` is preferable since it outputs additional
details (which function has been called and whether it is a startup or
shutdown error), uses HTML markup, and also provides a link to the
documentation, if configured.
Since these deprecation warnings have been introduced recently[1][2],
i.e. for PHP 8.4, there are no BC concerns.
[1] <e8ff7c70f9>
[2] <b36eac94d2>
Co-authored-by: Máté Kocsis <kocsismate90@gmail.com>
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