[move][lints] warn on uneeded return

[cgswords]

Description

Check for and report unnecessary returns.

Test Plan

New test case added

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Type of Change (Check all that apply)

• [ ] protocol change
• [ ] user-visible impact
• [ ] breaking change for a client SDKs
• [ ] breaking change for FNs (FN binary must upgrade)
• [ ] breaking change for validators or node operators (must upgrade binaries)
• [ ] breaking change for on-chain data layout
• [ ] necessitate either a data wipe or data migration

Release notes

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Name	Status	Preview	Comments	Updated (UTC)
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