feat(fix): ignore `todo!` and `unimplemented!` in `if_same_then_else`
close: #8836
take over: #8853
This PR adds check `todo!` and `unimplemented!` in if_same_then_else.
( I thought `unimplemented` should not be checked as well as todo!.)
Thank you in advance.
changelog: ignore todo! and unimplemented! in if_same_then_else
r? `@Jarcho`