minor #36546 [Mailer] Add a comment to avoid more wrong PRs on this p…

…iece of code (fabpot)

This PR was merged into the 4.4 branch.

Discussion
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[Mailer] Add a comment to avoid more wrong PRs on this piece of code

| Q             | A
| ------------- | ---
| Branch?       | 4.4 <!-- see below -->
| Bug fix?      | no
| New feature?  | no <!-- please update src/**/CHANGELOG.md files -->
| Deprecations? | no <!-- please update UPGRADE-*.md and src/**/CHANGELOG.md files -->
| Tickets       | Numerous bogus PRs <!-- prefix each issue number with "Fix #", if any -->
| License       | MIT
| Doc PR        | n/a

Commits
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444e616 [Mailer] Add a comment to avoid more wrong PRs on this piece of code

src/Symfony/Component/Mailer/Transport/Smtp/EsmtpTransport.php

@@ -106,6 +106,9 @@ protected function doHeloCommand(): void
 
         /** @var SocketStream $stream */
         $stream = $this->getStream();
+        // WARNING: !$stream->isTLS() is right, 100% sure :)
+        // if you think that the ! should be removed, read the code again
+        // if doing so "fixes" your issue then it probably means your SMTP server behaves incorrectly or is wrongly configured
         if (!$stream->isTLS() && \defined('OPENSSL_VERSION_NUMBER') && \array_key_exists('STARTTLS', $capabilities)) {
             $this->executeCommand("STARTTLS\r\n", [220]);