minor #13654 Deprecated the NumberToLocalizedStringTransformer constants (javiereguiluz)

This PR was squashed before being merged into the master branch.

Discussion
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Deprecated the NumberToLocalizedStringTransformer constants

Fixes #13646.

Commits
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56a4010 Deprecated the NumberToLocalizedStringTransformer constants

Author: javiereguiluz

reference/forms/types/options/rounding_mode.rst.inc

@@ -1,32 +1,38 @@
 rounding_mode
 ~~~~~~~~~~~~~
 
-**type**: ``integer`` **default**: ``NumberToLocalizedStringTransformer::ROUND_HALF_UP``
+**type**: ``integer`` **default**: ``\NumberFormatter::ROUND_HALFUP``
 
-If a submitted number needs to be rounded (based on the `scale`_
-option), you have several configurable options for that rounding. Each
-option is a constant on the :class:`Symfony\\Component\\Form\\Extension\\Core\\DataTransformer\\NumberToLocalizedStringTransformer`:
+If a submitted number needs to be rounded (based on the `scale`_ option), you
+have several configurable options for that rounding. Each option is a constant
+on the ``\NumberFormatter`` class:
 
-* ``NumberToLocalizedStringTransformer::ROUND_DOWN`` Round towards zero. It
+* ``\NumberFormatter::ROUND_DOWN`` Round towards zero. It
   rounds ``1.4`` to ``1`` and ``-1.4`` to ``-1``.
 
-* ``NumberToLocalizedStringTransformer::ROUND_FLOOR`` Round towards negative
+* ``\NumberFormatter::ROUND_FLOOR`` Round towards negative
   infinity. It rounds ``1.4`` to ``1`` and ``-1.4`` to ``-2``.
 
-* ``NumberToLocalizedStringTransformer::ROUND_UP`` Round away from zero. It
+* ``\NumberFormatter::ROUND_UP`` Round away from zero. It
   rounds ``1.4`` to ``2`` and ``-1.4`` to ``-2``.
 
-* ``NumberToLocalizedStringTransformer::ROUND_CEILING`` Round towards positive
+* ``\NumberFormatter::ROUND_CEILING`` Round towards positive
   infinity. It rounds ``1.4`` to ``2`` and ``-1.4`` to ``-1``.
 
-* ``NumberToLocalizedStringTransformer::ROUND_HALF_DOWN`` Round towards the
+* ``\NumberFormatter::ROUND_HALFDOWN`` Round towards the
   "nearest neighbor". If both neighbors are equidistant, round down. It rounds
   ``2.5`` and ``1.6`` to ``2``, ``1.5`` and ``1.4`` to ``1``.
 
-* ``NumberToLocalizedStringTransformer::ROUND_HALF_EVEN`` Round towards the
+* ``\NumberFormatter::ROUND_HALFEVEN`` Round towards the
   "nearest neighbor". If both neighbors are equidistant, round towards the even
   neighbor. It rounds ``2.5``, ``1.6`` and ``1.5`` to ``2`` and ``1.4`` to ``1``.
 
-* ``NumberToLocalizedStringTransformer::ROUND_HALF_UP`` Round towards the
+* ``\NumberFormatter::ROUND_HALFUP`` Round towards the
   "nearest neighbor". If both neighbors are equidistant, round up. It rounds
   ``2.5`` to ``3``, ``1.6`` and ``1.5`` to ``2`` and ``1.4`` to ``1``.
+
+.. deprecated:: 5.1
+
+    In Symfony versions prior to 5.1, these constants were also defined as aliases
+    in the :class:`Symfony\\Component\\Form\\Extension\\Core\\DataTransformer\\NumberToLocalizedStringTransformer`
+    class, but they are now deprecated in favor of the ``\NumberFormatter`` constants.