minor #8697 Added translations directory to file tree (fridde, weaverryan)

This PR was merged into the 4.0 branch.

Discussion
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Added translations directory to file tree

The description below the directory tree references the translation directory, which is missing in the tree.

Commits
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4f628d7 adding other dirs
e0fa5cb Update flex.rst

Author: xabbuh

setup/flex.rst

@@ -137,6 +137,9 @@ following directory structure, which is the same used by default in Symfony 4:
 .. code-block:: text
 
     your-project/
+    ├── assets/
+    ├── bin/
+    │   └── console
     ├── config/
     │   ├── bundles.php
     │   ├── packages/
@@ -148,6 +151,9 @@ following directory structure, which is the same used by default in Symfony 4:
     │   ├── ...
     │   └── Kernel.php
     ├── templates/
+    ├── tests/
+    ├── translations/
+    ├── var/
     └── vendor/
 
 This means that installing the ``symfony/flex`` dependency in your application