minor symfony#14480 Change "-t" to "--track" to be more explicit (michaelKaefer)

This PR was submitted for the 5.1 branch but it was merged into the 3.4 branch instead.

Discussion
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Change "-t" to "--track" to be more explicit

Commits
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08ded89 Change "-t" to "--track" to be more explicit

Author: wouterj

contributing/code/pull_requests.rst

@@ -159,7 +159,7 @@ Or, if you want to provide a bug fix for the ``3.4`` branch, first track the rem
 
 .. code-block:: terminal
 
-    $ git checkout -t origin/3.4
+    $ git checkout --track origin/3.4
 
 Then create a new branch off the ``3.4`` branch to work on the bug fix: