minor #19602 chore: improve TOC numbered lines (94noni)

This PR was submitted for the 7.0 branch but it was merged into the 5.4 branch instead.

Discussion
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chore: improve TOC numbered lines

Unsure if its the only thing to change
but refers to TOC numbering display
![Capture d’écran 2024-02-26 à 07 50 22](https://github.com/symfony/symfony-docs/assets/1358361/a8a247c5-43cc-4d98-a309-f68ed72b3fd8)

Commits
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13d7707 Update http_kernel.rst

Author: javiereguiluz

components/http_kernel.rst

@@ -489,7 +489,7 @@ as possible to the client (e.g. sending emails).
 
 .. _component-http-kernel-kernel-exception:
 
-Handling Exceptions: the ``kernel.exception`` Event
+9) Handling Exceptions: the ``kernel.exception`` Event
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 **Typical Purposes**: Handle some type of exception and create an appropriate