Add new lint getter_prefixes

[faeroon]

---

implemented new check getter prefixes lint and meet UI test error

changelog: [getter_prefixes]

• Followed [lint naming conventions][lint_naming]
• Added passing UI tests (including committed .stderr file)
• cargo test passes locally
• Executed cargo dev update_lints
• Added lint documentation
• Run cargo dev fmt

Fixes #1673. Based on comments of previous PR #3616. Changes comparing to previous:

1. lint checks only public inherent associated methods with return type
2. lint checks method bodies have trivial logic and return inner state

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[github-actions]

Lintcheck changes for e0a60fe

Lint	Added	Removed	Changed
clippy::getter_prefixes	290	0	0

This comment will be updated if you push new changes

[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.