[PHPUnitBridge] Fix copy/paste error

Due to my own screw-up, I copy pasted the same text in all the changes from my previous PR, #7211, as it's clearly visible from the compare view: https://github.com/symfony/symfony-docs/pull/7211/files

This PR fixes the issue, reverting back the part of text that should be unaffected by my intended changes.

Author: Jean85

components/phpunit_bridge.rst

@@ -215,8 +215,8 @@ DNS-sensitive Tests
 -------------------
 
 .. versionadded:: 3.1
-    The ability to disable the deprecation helper was introduced in the 3.1 
-    version of this component.
+    The mocks for DNS related functions were introduced in the 3.1 version
+    of this component.
 
 Tests that make network connections, for example to check the validity of a DNS
 record, can be slow to execute and unreliable due to the conditions of the