error in the example of how to test a command with a DialogHelper

[ptitlazy]

In the example simple quotes are used instead of double quotes
When giving the input stream to be used by the command, 'Test\n' should be "Test\n", otherwise the line ending is not taken a such.

https://github.com/symfony/symfony-docs/blob/master/components/console/helpers/dialoghelper.rst#testing-a-command-which-expects-input

Seen in all versions.