minor #7553 Fix version notice rendering (xelan)

This PR was merged into the 3.2 branch.

Discussion
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Fix version notice rendering

Commits
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4d8c05c Fix version notice rendering

Author: xabbuh

components/yaml.rst

@@ -206,7 +206,7 @@ changed using the third argument as follows::
 Numeric Literals
 ................
 
-versionadded:: 3.2
+.. versionadded:: 3.2
     Support for parsing integers grouped by underscores was introduced in
     Symfony 3.2.