minor #8264 Update parameters.rst (afurculita)

This PR was squashed before being merged into the 3.3 branch (closes #8264).

Discussion
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Update parameters.rst

Setting php constants as parameters is different for each configuration format.

Commits
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4dc9cc7 Update parameters.rst

Author: xabbuh

service_container/parameters.rst

@@ -242,9 +242,7 @@ See :doc:`/configuration/external_parameters`.
 Constants as Parameters
 -----------------------
 
-Setting PHP constants as parameters is also supported.
-To take advantage of this feature, map the name of your constant to a parameter
-key and define the type as ``constant``.
+Setting PHP constants as parameters is also supported:
 
 .. configuration-block::