Extend unnecessary_lazy_eval to cover bool::then -> bool::then_some

[joshtriplett]

fixes #9097

changelog: Extend unnecessary_lazy_eval to convert bool::then to bool::then_some

[rust-highfive]

r? @llogiq

(rust-highfive has picked a reviewer for you, use r? to override)

[joshtriplett]

This is WIP because I haven't managed to get the change to actually fire on the test case; I would appreciate advice on what I'm missing.

[ghost]

This should probably have a MSRV check for 1.62.

[flip1995]

cargo dev fmt and this should be good to go.

[joshtriplett]

@flip1995 Done.

[flip1995]

@bors r+

Thanks!

[bors]

📌 Commit b7230d4 has been approved by flip1995

[bors]

⌛ Testing commit b7230d4 with merge f93d418...

[bors]

☀️ Test successful - checks-action_dev_test, checks-action_remark_test, checks-action_test
Approved by: flip1995
Pushing f93d418 to master...