minor #13181 Update versioning.rst (abdounikarim)

This PR was submitted for the 5.0 branch but it was squashed and merged into the 3.4 branch instead.

Discussion
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Update versioning.rst

alt missing alt

Commits
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7886b8d Update versioning.rst

Author: OskarStark

frontend/encore/versioning.rst

@@ -67,7 +67,7 @@ like normal:
 
 .. code-block:: html+twig
 
-    <img src="{{ asset('build/images/logo.png') }}">
+    <img src="{{ asset('build/images/logo.png') }}" alt="ACME logo">
 
 Troubleshooting
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