minor #17997 Updated all the README files (javiereguiluz)
minor #17997 Updated all the README files (javiereguiluz)

This PR was squashed before being merged into the 2.3 branch (closes #17997).

Discussion
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Updated all the README files

| Q             | A
| ------------- | ---
| Branch        | 2.3
| Bug fix?      | no
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | -
| License       | MIT
| Doc PR        | -

Related to #17995.

Commits
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2e81248 Updated all the README files

symfony/http-foundation,symfony/HttpFoundation