[mem_replace_with_default] No longer triggers on unused expression

[GabrielBFern]

changelog:[mem_replace_with_default]: No longer triggers on unused expression

Change [mem_replace_with_default] to not trigger on unused expression because the lint from #[must_use] handle this case better.

fixes: #5586

[rustbot]

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[Jarcho]

Thank you. @bors r+

[bors]

📌 Commit 8355591 has been approved by Jarcho

It is now in the queue for this repository.

[bors]

⌛ Testing commit 8355591 with merge 3e3a09e...

[bors]

☀️ Test successful - checks-action_dev_test, checks-action_remark_test, checks-action_test
Approved by: Jarcho
Pushing 3e3a09e to master...