minor #17463 [Security] Document access_token.token_handler.oidc_user_info (vincentchalamon)

This PR was squashed before being merged into the 6.3 branch.

Discussion
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[Security] Document `access_token.token_handler.oidc_user_info`

Refs symfony/symfony#48272

- [x] document `oidc_user_info` token handler
- [x] document `oidc` token handler

Commits
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5b53159 [Security] Document `access_token.token_handler.oidc_user_info`

Author: javiereguiluz