minor #7762 Fixed code block under "Custom Messages" (superhaggis)

This PR was submitted for the 3.2 branch but it was merged into the 2.7 branch instead (closes #7762).

Discussion
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Fixed code block under "Custom Messages"

Very minor typo correction!

Commits
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32a5c9c Fixed code block under "Custom Messages"

Author: xabbuh

components/console/helpers/progressbar.rst

@@ -308,7 +308,7 @@ before displaying these messages, you must define your own custom format::
     $progressBar->setFormat('custom');
 
 Now, use the ``setMessage()`` method to set the value of the ``%message%``
-placeholder before displaying the progress bar:
+placeholder before displaying the progress bar::
 
     // ...
     $progressBar->setMessage('Start');