minor #6225 [Reference][Forms] add versionadded directive for range type (xabbuh)

This PR was merged into the 2.8 branch.

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[Reference][Forms] add versionadded directive for range type

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211f3a6 add versionadded directive for range type

Author: xabbuh

Diff for: reference/forms/types/range.rst

@@ -4,6 +4,9 @@
 RangeType Field
 ===============
 
+.. versionadded:: 2.8
+    The ``range`` type was introduced in Symfony 2.8.
+
 The ``RangeType`` field is a slider that is rendered using the HTML5
 ``<input type="range" />`` tag.