[significant_drop_tightening] Ignore inexpensive statements

[c410-f3r]

Not all statements that follow the last use of a lock guard are expensive and can therefore be ignored by the lint.

pub fn foo() -> i32 {
    let mutex = Mutex::new(1);
    let lock = mutex.lock().unwrap();
    let rslt = *lock;
    let another = rslt;
   another
}

---

changelog: [significant_drop_tightening]: No longer lints for inexpensive statements after the lock guard
#10363

[rustbot]

r? @xFrednet

(rustbot has picked a reviewer for you, use r? to override)

[xFrednet]

Looks good to me, thank you!

@bors r+

[bors]

📌 Commit 747f81e has been approved by xFrednet

It is now in the queue for this repository.

[bors]

⌛ Testing commit 747f81e with merge e1da002...

[bors]

☀️ Test successful - checks-action_dev_test, checks-action_remark_test, checks-action_test
Approved by: xFrednet
Pushing e1da002 to master...