Heredoc containing \n cannot be parsed for indenting

Playground link

Input:

<?php
function foo() {
    $message .= <<<EOT
    Please read this message.\n  We apologize for the inconvenience.
    EOT;
}

Output:

Invalid body indentation level (expecting an indentation at least 4) on line 5

  3 |     $message .= <<<EOT
  4 |     Please read this message.\n  We apologize for the inconvenience.
> 5 |     EOT;
    |    ^
  6 | }
  7 |

Expected:

<?php
function foo() {
    $message .= <<<EOT
    Please read this message.\n  We apologize for the inconvenience.
    EOT;
}

Basically, the \n in the middle of the heredoc appears to confuse either the parser or prettier.

Start with the linked Prettier PHP Playground and reproduce the heredoc case containing the literal \n. Trace whether parsing or indentation validation mishandles that content, then add a regression test for the example. Done means the input formats successfully without an indentation error and preserves the expected heredoc output.