minor #16904 [Testing] [PHPUnit Bridge] Fix link text (MaximePinot)

This PR was squashed before being merged into the 4.4 branch.

Discussion
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[Testing] [PHPUnit Bridge] Fix link text

The text link is the page title instead of the section title:

![Screenshot from 2022-06-21 16-05-40](https://user-images.githubusercontent.com/13469986/174822489-34f55d66-c732-413f-b309-ec8eea0a094c.png)

Commits
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e834d34 [Testing] [PHPUnit Bridge] Fix link text

Author: javiereguiluz

components/phpunit_bridge.rst

@@ -48,7 +48,7 @@ Installation
     always use its very latest stable major version to get the most accurate
     deprecation report.
 
-If you plan to :ref:`write-assertions-about-deprecations` and use the regular
+If you plan to :ref:`write assertions about deprecations <write-assertions-about-deprecations>` and use the regular
 PHPUnit script (not the modified PHPUnit script provided by Symfony), you have
 to register a new `test listener`_ called ``SymfonyTestsListener``: