Cleanup: do not handle methods from several places

[samueltardieu]

Some methods lints were handled in the methods module outside the check_methods() function.

changelog: none

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[rustbot]

This PR was rebased onto a different master commit. Here's a range-diff highlighting what actually changed.

Rebasing is a normal part of keeping PRs up to date, so no action is needed—this note is just to help reviewers.