minor symfony#20502 [Config] Add ifFalse() (OskarStark)

This PR was merged into the 7.3 branch.

Discussion
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[Config] Add `ifFalse()`

Fix symfony#20499

Commits
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3596f8c Add ifFalse()

Author: javiereguiluz

components/config/definition.rst

@@ -815,6 +815,7 @@ A validation rule always has an "if" part. You can specify this part in
 the following ways:
 
 - ``ifTrue()``
+- ``ifFalse()``
 - ``ifString()``
 - ``ifNull()``
 - ``ifEmpty()``
@@ -833,6 +834,10 @@ A validation rule also requires a "then" part:
 Usually, "then" is a closure. Its return value will be used as a new value
 for the node, instead of the node's original value.
 
+.. versionadded:: 7.3
+
+    The ``ifFalse()`` method was introduced in Symfony 7.3.
+
 Configuring the Node Path Separator
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