[3.2] Fix vale errors and some warnings in the "OpenID Connect (OIDC) and O…

[rolfedh]

…Auth2 Client and Filters Reference Guide"

Manually cherry-picked 420fca3 from #37020 in main' to the 3.2branch. While fixing the merge conflict, I excluded the new section inmain, [GraphQL client integration](https://github.com/quarkusio/quarkus/blob/main/docs/src/main/asciidoc/security-openid-connect-client-reference.adoc#graphql-client-integration) from this 3.2` PR.

FYI @aloubyansky

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[rolfedh]

@sberyozkin Rather than shorten the title of this PR, I matched the title of the PR in main. I did this because some teams prefer that the two titles (main/3.2 in this case) match each other. Not sure what the preference of this team is.