[Routing] Update routing.rst

[vimalgorasiya]

Hello,

This pull request enhances the code snippets under the Matching HTTP Methods section by adding the missing import namespaces for Symfony components. The updated code in src/Controller/BlogApiController.php now includes the necessary use statements, ensuring clarity and correctness.

If further improvements or updates are needed, please let me know.

Thanks.

[javiereguiluz]

Vimal, thanks for this contribution.

In Symfony Docs, we usually only show the full use statements the first time they are used ... the rest of the examples of the same page just show the // ... instead of repeating the imports. But, in this case this is the second time these imports appear ... and the first time it's a bit disconnected from this one. So, let's merge it.

So, generally speaking, let's not replace // ... in all the examples by the actual import ... only if they haven't been included before in the same page. Thanks!

Congrats on your first Symfony Docs contribution 🎉