Removed leftover 3.4 versionadded directive

Author: wouterj

translation/xliff.rst

@@ -9,10 +9,6 @@ has some specific features.
 Adding Notes to Translation Contents
 ------------------------------------
 
-.. versionadded:: 3.4
-
-    The feature to load and dump translation notes was introduced in Symfony 3.4.
-
 Sometimes translators need additional context to better decide how to translate
 some content. This context can be provided with notes, which are a collection of
 comments used to store end user readable information. The only format that