minor #17326 [Console] docs(console): add caution for testing option (jeremyhalin)

This PR was submitted for the 6.1 branch but it was merged into the 5.4 branch instead.

Discussion
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[Console] docs(console): add caution for testing option

Add a caution about `InputOption::VALUE_NONE` testing. Passing only a value without a key doesn't work and can lead to misunderstanding.

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Commits
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26a7fab docs(console): add caution for testing option

Author: javiereguiluz

console.rst

@@ -546,6 +546,15 @@ call ``setAutoExit(false)`` on it to get the command result in ``CommandTester``
         $application->setAutoExit(false);
 
         $tester = new ApplicationTester($application);
+        
+
+.. caution::
+
+    When testing ``InputOption::VALUE_NONE`` command option, be sure to pass an empty
+    value like so::
+    
+        $commandTester = new CommandTester($command);
+        $commandTester->execute(['--some-option' => '']);
 
 .. note::